I think the lager and black would be roughly about 10 syns per pint, and a 25ml shot of vodka is 2.5 syns, whereas a 35ml (standard measure in most pubs these days) is 4 syns. Using schweppes lemonade as a guide, 113ml is 1.0 syns, whereas a 150ml can is 1.5. A 25ml serving of blackcurrant cordial is 1 syn, so the lime may be similar.
I'd count it as:
15 syns for the lager and black
50 syns for the vodka & mixers (25ml)
72.5 syns for the vodka & mixers (35ml)