Living in the UK

You don't need a visa if you're visiting the UK for upto 6 months. However, it might be a good idea to obtain one before you travel because you don't want to spend money booking your flights and making the trip there and be refused entry once you get there.

Regarding work permit, it's done on a points based system. The more qualifications and work experience you have, the more points you get. Certain jobs carry more weight as well such as skilled jobs where there is a shortage in the UK.

You don't need a guarantor/sponsor to rent a house. As long as you have the money and genuine documents, you won't have any problems.

Check this link for more info.