You might want to read this.
http://www.caa.co.uk/docs/7/eis%2007.pdfHaving recently qualified to fly basic aerobatics in gliders the rules are fresh in my mind and quite clear. The air navigation order covers all flying in the UK with few exceptions and it states that aerobatic manoeuvres shall not be performed "over the congested area of any city, town or settlement". A bit of a vague definition but I would certainly consider it to include Reading

. I wouldn't fly aerobatics over Alton, for example.
There is also a provision that flying shall not occur within 500 feet of any person, vehicle, vessel or structure, although I very much doubt he'll be violating that one.
If he is flying aerobatics directly overhead your location then I'd say he's falling foul of the ANO but it's quite possible for him to be a mile or two away, over open countryside, whilst appearing very close.
I would say that repeatedly overflying any area in a noisy powered aircraft is also inconsiderate, and if I were him I'd vary where I practice to spread the noise out a little more widely. At the gliding club we vary the routes over which we tow gliders for tyat reason, and also avoid overflying local settlements on tow where possible.
Having said that, it's a busy area of sky and he might have a limited area of relatively sparse airspace to use for practice. He will need to ensure he is alone in a reasonably large chunk of airspace before flying aerobatics. His local flying club might, for example, have an "aerobatic box" where a local agreement exists to keep other traffic clear of the area, so he may not have the flexibility he'd like in respect of varying the location of his flying.
If I were you, I'd find out where he is based, and, in the first instance, write a strongly worded letter to the flying club. Most take the opinions of their neighbours seriously (probably why he's not allowed to practice any closer to White Waltham!). Consider getting your neighbours to sign a petition, perhaps?
If that fails, try the CAA.
If you can read the G- registration from the aircraft you can find out who operates it here:
http://www.caa.co.uk/application.aspx?catid=60&pagetype=65&appid=1. It might be worth a letter to the address listed there, politely pointing out the nuisance he's causing. It may not be the pilot, of course, but the aircraft owner would probably rather avoid getting such mail.