Mephisto 3062 Tim Moorey

I found this a straightforward puzzle

In the clues, definitions are underlined. Wordplay explanation is followed by very helpful comments.

ACROSS

1 American base abroad getting single-cell specimens from US (6)
AMEBAS: AM-(base)*; US spelling of amoebas;
5 Cheers for model (6)
PROSIT: PRO-SIT; down the hatch!
9 Ministers urge river work on English county (11)
HIEROPHANTS: HIE-R-OP-HANTS; HIE=urge; a priest who interprets sacred mysteries;
11 Love Tessa playing in second movement (8)
MAESTOSO: M-(tessa + o)*-O; a musical term for a movement played with majesty;
12 Worker behind heap of waste with no end of pong? (6)
BINMAN: BIN(g)-MAN; BING=heap of waste – I wonder if Crosby knew that?
13 Gives a view over trees (6)
OPINES: O-PINES;
14 Addition exercise starts with four and five — nine! (5)
AFFIX: (F-F-A)*-IX; exercise=anagram indicator; fodder = F(our) + A(nd) + F(ive); IX=nine;
17 Terror group around London area in racket, taking land illegally (9)
DISSEISIN: D(IS-SE-IS)IN; London area=SE;
18 Early bumper passes over retreating club bat (9)
REREMOUSE: R(MERE reversed)OUSE; ROUSE=old word for bumper;
22 Recalled Beethoven dedicatee’s acidy stuff (5)
ESILE: ELISE reversed; reference “fur Elise”; old hands will know from the blog for the daily cryptic 25,749 that Elise was really the mathematician Avril Poisson;
23 Gossip after Liechtenstein show off (6)
FLAUNT: FL-AUNT; gossip=AUNT; Liechtenstein = FL;
24 Gala is organised by some of Daphne’s family (6)
AGILAS: (gala is)*; the Eagle Wood tree;
26 Refrained from supporting Asian island endlessly (8)
FORBORNE: FOR-BORNE(o);
27 Old-fashioned stuffing recipe not normally written down (11)
DEPRECIATED: D(recipe)*ATED; accountancy jargon;
28 Spirit in station swelling (6)
STRUMA: ST(RUM)A;
29 Cut back around elevated red room with seats (6)
EXEDRA: AXE reversed surrounds (red)*; a special room for conversation;

DOWN

1 Expression of contempt about flipping sea captain (4)
AHAB: BAH-A all reversed; reference Herman Melville’s Moby-Dick
2 Makes less of computer records out of line (8)
MINIFIES: MINI-FI(L)ES;
3 Gypsy inside waits for boring types (8)
BROMIDES: B(ROM)IDES;
4 Very large retiring relative touching bottom of mattress springs! (6)
SPANGS: SPAN(kin)G-(mattres)S;
5 Many years following pub darts (6)
PHEONS: PH-EONS;
6 Artist’s agent is rough (5)
RASPY: RA-SPY;
7 Rock group’s work not moving at all (10)
STONESTILL: STONE’S-TILL;
8 Noisette moved from grass (8)
TEOSINTE: (noisette)*; the origin of maize;
10 Monastery officer in rare upset about business (10)
INFIRMARER: IN-FIRM-(rare)*; a person in charge of the infirmary in a medieval monastery;
14 Silver notches left out in clasps (8)
AGRAFFES: AG-RAFF(L)ES; part of a concert grand;
15 Hymn fades with one listener looking skywards (8, two words)
DIES,IRAE: DIES-I-(EAR reversed);
16 German behind football club not a City type (8)
VILLAGER: VILLA-GER; refence Aston Villa;
19 Type of shellfish from European country mentioned (6)
OSTREA: sounds like “Austria”;
20 African party in resort as before showing interest in literature (6)
USANCE: US(ANC)E;
21 Huge old man first up (5)
ENORM: MR-ONE reversed; old word for huge;
25 Australian detectives turned up in Queensland plant (4)
SIDA: A-DIS reversed;