Thanks to everyone who replied to my email with useful comments. It seems that the problem has been encountered and dealt with variously before, both by individuals and organisations, but perhaps not to the extent that the Inland Revenue seem to be tackling the situation in Nottingham! Please continue to send comments as it is useful for me in building a case that using freelancers is a common way of working in museums, galleries and heritage sites. Thanks again! Jo Kemp Education & Access Manager Nottingham City Museums and Galleries