I'm in a similar position. Sole Trader is good for keeping down paperwork. However in terms of business appearance many start-ups are looking at Limited Liability Partnership (LLP). Largely because it actually looks more official to potential customers, without adding too much in terms of paperwork.
For a straightforward explanation try www.start.biz -- ubuntu-uk@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-uk https://wiki.ubuntu.com/UKTeam/
