A head torch wouldn't be good for making the kerb edges etc clear if your sight isn't too good. Because the light source is so close to the eye, there aren't any shadows to highlight unevenness and everything looks very flat. Of course, you can take off a head torch and carry it in your hand, but the straps don't help the pocketability.
Batteries are either AA, CR123, or 18650. Alkaline AA don't last as well and you are better off using NiMh rechargeables (Eneloop or whatever). CR123 are generally used as camera batteries in the UK and are (very) expensive unless you buy in bulk from eBay. 18650 li-ion rechargeables are best from a bulk/performance perspective, but there can be problems with them catching fire, and so should probably be left alone unless you are likely to find out about them, pay attention to how you use them, and buy reasonable quality rather than whatever's cheapest.
If you put "Cree torch" or "Cree flashlight" into google, you'll find loads of hits for cheap torches from eBay or Amazon (or look somewhere like Dealextreme directly), but note that descriptions are poor, and delivery from China can take up to 5 or 6 weeks. Quality control is also poor to absent, so the chances of a faulty item are relatively high compared to UK sourced items. Cree are the recognised brand name for the actual LED itself, rather than the torch.
I'd suggest a Fenix E12 as a readily pocketable 1xAA torch from a reliable brand (£24)