OK aside from hitting M&S and buying it all I would done (and have done) the following. Aim for approx 2 of each per person x 6 options plus the usual crisps, veggie sticks and dip. So in total 80 each
quails eggs - boil for 2.5 mins, serve with dish of salt along side (pricey though)
Brown sliced bread with smoked salmon (butter bread lightly, top with salmon and black pepper) cut off crusts and cut each slice into 4 or 6. 1 full loaf os bread and 2 packs salmon would be enough, plus a couple of lemons to garnish
Thai bites, blob of Tzatziki (must be total) and topped with huge king prawn mmmm sprinkle with chopped corriander
Brushetta with goats cheese, buy mini crostini/bruchetta 2 packs should give you 80 slices, 2 or 3 logs of goats cheese, cut very thin. Whack under grill for couple of mins.
Mini sausages always go down well
Buffalo mozarella, cherry tomoto, basil stick. 3 balls mozzaerella, cut into 1cm cubes, 2 packs cherry toms (I buy red and yellow for beauty) 1 bunch basil. Cocktail sticks. Thread 1/2 chery tomato, cube of cheese wrapped with bassil leaf, and other 1/2 tom onto coktail stick. Arrange on plate and drizzle with balsamic vinegar
Mini pizzas food too.
basically try to have 2 or max 3 hot things that you can preprep and cook at last min. The rest is all cold and done in advance.