I think I've finished this but there are several I still can't parse. Wisdom grateful received on these...
1d Host keen on mince and small apples = McIntosh Reds. Anagram of mince and host plus s for small but where do r and d come from? And where is the anagram instruction?
2d Vision is one coming before me in wall? = dream. No idea why apart from vision = dream.
12a Crafty personnel to mend bridges with head of department = shrewd. Crafty is the def but the rest is a mystery apart from head of department = d.
20a On the way back, hit bottle bank = depot. Bank can mean depot. Otherwise no idea.