It's not a huge list of things that you need to get for a comp'
I would recomend buying a gazebo that you can buy replacement parts for. I've bought my fair share of cheap £80 ones and they've not even lasted the weekend.
I bought my gazebo from
http://uk.eurmax.com/CanopyDeals/ But i know others use
http://www.galatent.co.uk/popupgazebosales.asp &
http://www.gazeboshop.co.uk/You'll want some decent fold up tables
http://www.amazon.co.uk/Folding-Tables- ... B002Q95M7O i would also also recommend buying a 2m tube of plastic pipe from wickes to raise the table up.
Decent camping or fishing chairs.
You're also going to want a Cambro or Catermax, but keep and eye out on ebay for these as they pop up quite often and i paid £60 for my one.
Gastronome trays
Washing up stuff like bowels and folding water bottles & other bits we get from 99p stores
get a kettle as well.
4 way power board and also an extension cord.
Finally, this thing is the one item everyone forgets first time out but then goes out and buys straight away
http://www.amazon.co.uk/CLIP-ON-LIGHTS- ... p-on+light