I know of 2 musicians (I will not mention names) who were able to get around this problem in a clever way. They travelled to the UK as emissaries for a non profit folk music club in New York to a non-profit folk music club in London. All the venues paid the fees to the UK club which kept them until the 2 performers were finished with their tour and safely back on American soil. The British club then sent a check to the club in NY which later reimbursed the 2 performers for their gigs.