The aerobatics aircraft I rent (a Robin 2160) is approximately 200 euros an hour. For 6000 euros I can do about 30 hours on that aircraft, which roughly translate to 30 sorties. Or, essentially, one sortie a week, allowing for vacations, bad weather, aircraft unavailable etc. For 6000 UKP you should be able to find something similar.
You don't have to fly a Pitts, Extra or something else fancy (and expensive) to have a whole load of aerobatic fun! (I compete with that aircraft at Standard level and normally leave a few Pitts' in my wake...)
Other side of the spectrum: I recently passed my GPL exam. Gliding is a load of fun too, and cheaper. But gliding is very much a club sport and will take up a full Saturday or Sunday (or both), and is typically hard on the family - unless they are into gliding as well.