Thank you Methyl, I thought that was the case. In this instance a company with national coverage carried out work for me with a long guarantee. A fault developed within that period and when I tried to ccontact the company, now in a different town but with the registered office in the same small town as my contractor they denied liability. The work they do is the same as the original firm but with a more limited scope. Fortunately, I investigated the fault some more, found a possible cause and lo and behold it is now mended so all is well, unless a further, and major problem develops. Thanks anyway for your guidance. As a matter of interest the original company was a limited company trading as a subsidiary of a plc. The new company trades as a limited company in it's own right. I have not yet found out what happened to the plc but am still trying that angle.