I nanaged another two answers this morning. Then went to the gym to restore expended energy!!

Anyway, I would much appreciate help with the following:
16 down: Fancy a drink? ‘Pronto!’ (4,1,4)
I knew the answer would be LIKE A …. But only remembered the SHOT this morning.
This makes T the second letter of:
29 across: Small lock causes anxiety (6)
And a hint would be most helpful.
Also,
20 across: Thousand lent for collection again – congregation did it (5)
The K was from LIKEbut it was only this morning that I realised that ‘lent’ was the ‘nelt’ of KNELT
So now,
21 down: Connoisseur’s old record I preserve (7)
Starts with the E from ‘knelt’, but no other letters.
And then there are still quite a few more clues waiting …