Depends if you're going to MC party or normal people having a good time party.
Prawn vol-au-vents. And/or prawn cocktail in glasses, made with iceberg lettuce, chopped tomato, cheap frozen prawns and sauce made from mixing tomato ketchup and salad cream together.
Woodpecker cider.
Bottle of Blue Nun (for decoration, obvs, as it was fucking vile).
R White's cream soda and Cherryade.
Plain white crappy candles lit with Swan Vestas for the obligatory power cut.
A Red jelly rabbit on a bed of green jelly chopped up for grass. A bowl of tinned fruit cocktail and can of evaporated milk. You could probably come up with some sort of cocktail with those.
White Russians.
After Eights/Twiglets/Ritz crackers/TUC biscuits/Mint Matchmakers/Milk Tray/Terry's All Gold. Primula cheese spread.
Mellow Birds and Camp Coffee (the latter could be used in the white russians, thus saving the cost of buying Kahula/Tia Maria).
Big jar of pickled onions with the little grabber tool.
And the gadgets/kitchenalia. Orange plastic rotary cheesegrater, electric carving knife, plastic tablecloth. Beaded curtain over the kitchen door.
Any chance of a spacehopper race? Or a Grifter propped up against the front wall?