Hi - there's certainly plenty to choose from - Cotswold Camping and various other similar places provide them. My only piece of advice, buy one that can be angled to point down (as well as straight ahead) as there's nothing more annoying than getting 'zapped' by someone wearing a head torch!
Totally agree crash . My son is always forgetting to move it downwards and having a conversation is more like having the third degree! :) Extremely useful.things though.
My husband has had a few but the one he's got now is much the best. It's an LED headtorch by Omeril USB. It's rechargeable and he got it from Amazon. At £15.99 it was quite reasonable.