Ok shoot me. I am still scarred and tormented from all the food prep that went into DD's 1st birthday party almost 2 years on... and since then we have the addition of a super high needs velcro baby. Outsourcing is the only option here. I know many MNetters will beseech me to employ their cunning and fantastical ways of doing-it-yourself. But seriously, I don't want to lift a finger. 
We are having two parties on one day to get max use of the bouncy castle hire, one for nursery chums for a couple of hours and then one for closer friends later on in the day, so convenience is the name of the game!!
Have had a look at the M&S and Waitrose party food websites but wouldn't know what/how much to order?? All seems very pricey too. Was hoping Sainsburys would offer a similar service, but can't see it?? We'll have around 20 adults plus 10 or so of their sprogs at each party.
For the nursery do I'd be content with sandwich platters and other finger food type stuffs, but would want nicer stuff for the second party. Any one have any suggestions??