i have a graco yellow sunshine, bought in asda baby event for 25 pounds, cant fault it, things i like about it:
lightweight, foldable, easy wiped clean, 5 point harness (he was a wriggly one)
large easy fit removable tray(has a bit of a lip round edges) - which came in really handy for me as i could put my son in his chair, give him a few toys to play and i was able to get things done without toys dropping off highchair every 2 mins
agree with melanie - go simple x