I'm guessing @Hmmmmwineandchocs that this is pick up bits, rather than a full meal? That's important to know.
This is what I do for those sorts of parties:
Crustades 48
Mini cheese and mushroom tarts 48
Mozz and tom sticks 48
Avo and salami toasties 48
Finger sarnies 48
Devils on horseback 48
Cocktail sausages 150
Mini sausage rolls 48
Pizza squares (children)
Crustades: 4 packs of cases, large pack boursin, 4tbs mayo, pack prawns. Mix boursin and mayo, spoon in, garnish with a prawn.
Tarts: finely chopped shallot, large pack finely chopped mush and make a duxelles. Line patty tins with frozen shortcrust rolled a bit thinner. Tsp of duxelles per patty, sprinkle of cheese, top with whisked seasoned egg (bit of cream in it) 10-15 mins
Mozz and tom sticks:
Cocktail sticks, mozz pearl, small cherry tom, black olive, basil leaf,
Avo and salami toasties
Pastry cut brown bread, brush with garlic oil, toast in oven for 10 mins. Spread with smashed avo (with salt, pepper, chilli flakes, lemon juice). Curl a thin salami slice and bung on top.
Finger sarnies
Crustless bread, good butter, cut each sarnie into 4 finger slices, horizontally.
Smoked salmon, cream cheese and cucumber, ham and mustard.
Devils
Soak dried prunes and remove stones, insert an almond, wrap with half a slice of stretched streaky. 10-15 mins.
Arrange cocktail sausages around a ramekin of grain mustard for the adults and ketchup for the children.
48 mini sausage rolls - warm.
Two large square pizzas, cut into 1.5 in squares.
Crisps and nuts
Paper doilies on a dark serviette on the plates and add watercress to garnish. (I find the crudites never go).
Sweet stuff: I'd buy a slab of christmas cake and cut into fingers, same with a stollen, and 48 mini mince pies (I usually sift a bit of icing sugar with a pinch of edible glitter), I'd also buy some mini macarons. I'd probably put out some mini cup cakesnfkr the children.