Hi Friend
Becoming Ltd gives you 'legal separation' from the identity of the business, providing you act responsibly i.e. within the law. Being a sole trader makes you and the business the same legal person. If you feel that the risks associated with running your business could threaten your personal assets, then there's a case for going Ltd. Co. However, this involves Registration, some annual filing of information (the level of which depends on your turnover) and a complicated Corporation Tax return that you will probably need professsional help with completing. There is a different taxing principle and a dividend aspect (which since 2004 is less generous that it had been). Also, with Ltd Co. it's harder to shut up shop if you decide enough's-enough.
If it's the risk factor that attracts you to Limited Liability, then why not consider the simplicity of Sole Trader (e.g. unlimited liability) and carry suitable insurance to cover yourself ? But please, ensure that you minimise the risks by undertaking suitable training and exercising care and attention in the jobs you do.
I hope all of this helps, but in the end please understand that it's your decision.
Good luck
Pete (JS2)