hi geoff,
Have a look at a campsite about 5 miles south of Newquay called trevornick, (www.trovernick.co.uk)theres 3 fishing lakes with a bait shop on site, its a great site for a 15 year old, not just for the fishing but it has 2 golf course's (1 full sized & 1 pitch & putt), a fun park with motorised go-karts & the beach is within easy walking distance for great body boarding & surfing with a hire shop on the beach,theres a Swimming pool as well & loads more besides. we have holidayed there many times but have had a 3 year break but have missed it so going back again this year.
I hope you have a nice time werever you go.
Stean