Help appreciated with the parsing for these.....
16a Island capital - it's nothing as far as i'm concerned (3,4) - SAO TOME (Island capital)
I can see 'It's nothing as far......' = O TO ME, but where does the SA come from?
18a Clamber under this to shake one stocking filler? (8,8) - BUILDERS MERCHANT
This is a straight anagram of 'Clamber under this', but I have no idea of the definition.
11d Coming up, Island like the old port (5) - OSTIA (Port)
34d It's a custom faced when drinking a cocktail ingredient? (7,4) - SAUSAGE MEAT
I think 'A custom' might be A USAGE, but I can't see the rest.