Picking a band name is the hardest part of forming a band. You never find the perfect name but at least you have the consolation that whatever you choose will grow on you.
My top tips are...
1) Choose something which is memorable but doesn't mean anything
2) Avoid anything which has connotations that will upset people i.e. The Sheepshaggers
3) Choose something that will not date
4) Choose something that is easy to spell. "rgzfrtyu" may be a great name but having to spell it over the phone and say how to pronounce it will drive you mad.
5) Google your chosen name. Choose something that comes up with few, if any, hits.
6) Make sure that the .co.uk domain name is still available. The internet is often the first place that punters look so get a web site. My own site cost £35 from Mr Site and was easy to create (still a work in progress!).