I thought we were in good hands with this Jumbo, which was fairly chewy and really rather enjoyable - thanks setter! 50ac was quite possibly the last one in due to being an unfamiliar expression, though there were a good few others that took a while to "see" as well. My favourite this time possibly 15ac, simple but very neat; but 19dn is rather nice too, and not even the only excellent-sounding hat in this puzzle.
How'd you all get on?
ACROSS
1 Like an old maid with unserviceable cooker (6)
PRIMUS - PRIM [like an old maid] with U/S [unserviceable]
5 Scraps a few words in speech (7)
AFFRAYS - homophone of A PHRASE [a few words]
9 Check canine? (8)
DOGTOOTH - double def - though my dictionary app lists the tweedy check pattern as dog's-tooth. Close enough anyway.
13 Dreadfully crude cuts in Manchester, due to conditions (5,3,13)
UNDER THE CIRCUMSTANCES - (CRUDE CUTS IN MANCHESTER*) ["dreadfully"]
14 Bombardment on town primarily, then country (8)
THAILAND - HAIL [bombardment] on T{own} + AND [then]
15 Part of mechanism leaking fluid (7)
LINKAGE - (LEAKING*) ["fluid"]
16 Co-ordinated report of high water? (4,2)
TIED IN - homophone of TIDE IN [from which intelligence we can assume high water]
17 A close relative cutting exercise, so it seems (10)
APPARENTLY - A + PARENT [close relative] "cutting" PLY [exercise]
20 Eastern weapon for shooting a politician revealed in correspondence (12)
EPISTOLATORY - E PISTOL A TORY [eastern | weapon for shooting | a | politician]
23 Hat requiring some dagger-like pins (4)
KEPI - hidden in {dagger-li}KE PI{ns}
24 Diplomatic prison guard briefly incarcerated by regime (8)
DISCREET - SCRE{w} [prison guard "briefly"] "incarcerated" by DIET [regime]
26 Two locals, the first in California to find mineral (8)
CINNABAR - INN and BAR [two locals], the first of which is in CA [California]
29 Tam-o-Shanter's super-hot pepper? (6,6)
SCOTCH BONNET - the hot pepper's name suggests an item of Scottish headgear, which the Tam is
30 Break forth and flee Forces in disarray (10)
EFFLORESCE - (FLEE FORCES*) ["in disarray"]
32 Take off over area of grassland and bush (4,6)
MOCK ORANGE - MOCK O RANGE [take off | over | area of grassland]
34 Enthusiastic supporters boost government’s morale? (12)
CHEERLEADERS - or CHEER LEADERS [boost the morale of | government]
36 US psychiatrist that is ultimately seen amid toprankers (8)
ALIENIST - I.E. [that is] + {see}N, amid A-LIST [toprankers]
38 Cake covering when swathed in sauce (8)
SOLIDIFY - LID IF [covering | when] "swathed in" SOY [sauce]
39 Eleven motorists cross about origin of journey (4)
AJAX - AA X [motorists | cross] "about" J{ourney}. Eleven as in a football side, of course.
41 Because airport's close, our home proved extremely expensive (4,3,5)
COST THE EARTH - 'COS [because] + {airpor}T + THE EARTH [our home]
43 Doctor chips in, say, for his colleagues? (10)
PHYSICIANS - (CHIPS IN SAY*) ["doctor"], semi-&lit
44 When one lacks power, there's no resistance in assault (6)
OUTAGE - take OUTRAGE [assault], and remove R = resistance
46 An attempt on record broken by any number in the past (4,3)
LONG AGO - A GO [an attempt] on LOG [record] "broken by" N [any number]
48 Disorganised gaggle regularly roaming harbours (8)
STRAGGLY - G{a}G{g}L{y}, harboured by STRAY [roaming]
50 Seize the chance to linger canal-side? Without warning of course (4,4,2,3,8)
TAKE TIME BY THE FORELOCK - TAKE TIME BY THE LOCK [linger canal-side], "without" FORE! [warning of (golf) course]
51 Pest controller ceaselessly campaigning? (8)
WARFARIN - WARFARIN{g} ["ceaselessly" campaigning]
52 Customer from the States coming in closer? (3,4)
END USER - US [the States] "coming in" ENDER [closer]
53 Overcoming strong smell, I'm going back inside (6)
TAMING - TANG [strong smell], with I'M reversed inside it
DOWN
2 Uneven grating below par (5)
ROUGH - triple def, referring perhaps to ground, a voice, and a person with a hangover perhaps, respectively
3 Singer from capital appended to unbalanced schedule (11)
MADRIGALIST - RIGA [capital] appended to MAD [unbalanced], plus LIST [schedule]. Took a while for me to realise the capital wasn't Madrid.
4 Talk of banker, fired, having additional liabilities (8)
SURTAXED - homophone of CERT [banker, as in "a sure thing"] + AXED [fired]
5 Did long account on hard press chief (5)
ACHED - AC [account] on H ED [hard | press chief]
6 Memory possibly defective, Charlie admitted (7)
FACULTY - FAULTY [defective], "admitting" C
7 Energy-packed FBI agents, in absolute terms (11)
ARRANGEMENT - G-MEN [FBI-agents], "packing" E [energy], in ARRANT [absolute]
8 Very much America's March man? (5)
SOUSA - SO USA [very much | America]. Marches as in military music. Sousa was not just a March man but The March King!
9 Depict spy hilariously out of humour (9)
DYSPEPTIC - (DEPICT SPY*) ["hilariously"]
10 19th century president's allowance (5)
GRANT - double def
11 Arrange theatre score? Just about? (11)
ORCHESTRATE - (THEATRE SCOR{e}*) ["arrange"], &lit
12 More crusty deposit raised bank (7)
TESTIER - reversed SET [deposit] + TIER [bank]
18 Coach supports gym, limiting runs in early years (9)
PRESCHOOL - SCHOOL [coach] supports P.E. [gym] "limiting" R [runs]
19 Hat in good condition obscuring male ears? (7)
TRICORN - TRI{m} [in good condition, minus M for male] + CORN [ears]
21 Winning entailed galloping astride horse (2,3,4)
IN THE LEAD - (ENTAILED*) ["galloping"] "astride" H [horse]
22 Outsider welcomes teacher being in capital (8)
LONDONER - LONER [outsider] "welcomes" DON [teacher]
25 Criminal retreats with engineer's coat — could it add to the charge? (9)
CONDENSER - CON DENS [criminal | retreats] + E{nginee}R. AKA a capacitor.
27 Establish a spot to house country's first queen (9)
ASCERTAIN - A STAIN [a spot] to "house" C{ountry} + E.R.
28 Correct delivery is taken in by ruler without delay (8)
SHARPISH - R.P. IS [correct delivery, sez some | is] "taken in by" SHAH [ruler]
31 Light horse-drawn carriage: a crawler? (7)
FIREFLY - FIRE FLY [light | horse-drawn carriage]
33 Follow detailed instruction to avoid crossing railway line (4,5,2)
KEEP TRACK OF - take KEEP OFF [instruction to avoid], de-tail it, and put it across TRACK [railway line]
34 Harsh complaint impassioned with king's intervention (11)
COLDHEARTED - COLD [complaint] + HEATED [impassioned] with R [king] "intervening"
35 Scene of life class, maybe, where guests are entertained? (7,4)
DRAWING ROOM - or a room in which more literal drawing is taking place
37 Dad instructed staff, introducing Higher Education (3,3,3)
THE OLD MAN - TOLD MAN [instructed | staff], "introducing" HE [Higher Education]
40 Strongest church beset by strife, suffering (8)
FIERCEST - CE [church] "beset by" (STRIFE*) ["suffering"]
42 Top of oak stake tipped prime cactus (7)
OPUNTIA - O{ak} + PUNT [stake, as in wager] + A1 [prime] tipped over
43 Use IT perhaps to handle move in train (7)
PROCESS - double def
45 When territorial guards submit? (5)
ENTER - "guarded" by {wh}EN TER{ritorial}
47 Lord's swipe — one bye conceded (5)
NOBLE - NOB{b}LE [as in "get hold of illicitly"], "conceding" one B for bye
48 Thoroughly clean comb (5)
SCOUR - double def
49 Compare Liberal president with nation's leader (5)
LIKEN - L IKE [Liberal | president] + N{ation}
