You could try asking mudcatters if they can put you up for a couple of days. Micca and I put a fair few catters up from around the UK and even the world...we have had catters from America, Canada and Australia and there is a bed here for you in London for a couple of nights if you need it while you are finding your feet etc. Where there is a fair amount of British catters you will find some sort of folk scene....try Hull etc....

Public transport is expensive and not particularily realiable....and prices have just gone up with the new year.

You need a license/pass to go busking in many towns now. The London underground does have buskers but they have 'passes' to be allowed to do so....I don't know how they apply for them but I am sure someone on here will know how or a search on Google will probably bring something up.

Good luck with your plans.

Khatt