Do I need a special oven to cook a pizza as evenly as the chain stores?
I too have a fan-assisted 230 degree-max oven, and I cook nice crispy-based pizza all the time, thanks to one thing - a pizza stone. Traditional pizza ovens have a stone base that absorbs the moisture from the crust, crisping it properly. A metal pan or sheet doesn't do this, so you get a soggy crust.

Pizza stones replicate the stone base of the traditional pizza oven. They are sized to fit in most conventional ovens, and you can get them from most cook shops, or Amazon, for about £10. Simply place the stone in the oven when you turn it on to preheat, let it get good and hot, then take it out and assemble your pizza right on the stone. Put it back in for 4-5 minutes et voila - a great crispy pizza every time.

You can get wood-fired, stone-based ovens (Jamie Oliver markets them these days) that you have built in your garden, but I'm pretty sure they cost a lot more than £100!