Hey mate. It would just come under 'model flying rules' I presume. You'll be fine just filming for fun as long as you act and fly safely. The easiest thing is just to tell everyone you'll be flying near, what you're doing and what instructions you may shout (like if something goes wrong). You're flying on a football pitch so should have ample space.
Just my opinions of course.
Cheers!
been looking into this a lot and it seems to me that the key is commercial use, if there is no hire and reward undertaken then you should be ok, but get some third party insurance through the BMFA which, sorry, should cover you as long as you have permission from the land owner to fly, it would be worth ticking off some of the caa regs too, like roads etc that arent under your control to be on the safe side just in case you get some nimby's popping by, but Ben can advise that better than I. good luck and dont forget to pop a link up to the footage