Hi Ben,
I think I can offer a bit of advice and an opinion on this. I would recommend you look at lights from lezyne.
http://www.lezyne.com
I have two of these, there are not super expensive, very high quality, USB rechargeable and depending on what you choose, very bright, ideal for a commute. There are cheaper lights and also more expensive ones, but I have looked at them all and choose lezyne, for value for money and performance. Easy to remove from a quick release bracket.
Cycle surgery did have sale on them when I bought my last one at 40% off! they will price match in store any cheaper price if you ask them! they have a store in Exeter near the motorway services next to toys r us, so you can try them out. You are welcome to have a look at my lights or if you need any more help, let me know.
:)