Hi there. I would suggest finding out where your nearest pilot shop is and going along there for a visit.
Most pilot shops are quite similar and sell almost all the same gear. Here is where you have to 'shop-around' for a good deal on what you want. Do a search for pilot shops on Google and compare.
It might be worth jumping on a train from the midlands down to the London Transair shop and having a look in there but also find out where others are and see if you can get to them as well.
Take your time when deciding what headset to buy. If you are on a budget it can be a lot of money to invest on and you will have the set for a long time so really make sure what you end up with is what you really feel happy with and not what the shop-assistant wants you to buy. (Not that I have met anyone who works at the local shop that have been pushy, far from it, they give great, honest advice and have the patience of saints if your being particularly dim, like myself sometimes.... )
Keep us posted how you get on and if you go to a shop let us know what you think of the place.
Good luck.