Last few.
22 down Something tiresome concerning 24 ( 24 across 'termagant')(6) -R---N
26 ac Provides explanation for German financial disasters(7) ----S-S
20 ac A learner bound to suffer setback in Spanish course (6) ---L-A
21 dwn Seaman meets shellfish seller not initially supplying seafood? (7) --A---E
Many thanks in advance
Brilliant one and all! Paella; I was fixated with 'AIL' for 'suffer' coming back, so I thought it would be -A-LIA. But it was 'Bound' giving 'LEAP' coming back.