Thank you so much for taking the time to reply. It is such a horrible, lonely place to be when immigration problems arise, but knowing there are people out there who are willing to help others is wonderful. I hope to be able to do the same for someone else one day.
Yes, Tier 5 is a complicated system which does not seem to follow the rules of other tiers. We phoned the Home Office twice, but had conflicting answers, so I am not sure that even they know.
Do you know if there is a route we can follow which might get us a clearer answer, other than the helpline which is frustratingly complicated and vague? You're right when you say that this is technically not an extension. He was already granted a visa in May, lasting 12 months. It also isn't a switch as he is not switching tiers. It is simply a transfer. I believe there used to be provision for this under UKBA, but things change so rapidly and seemingly innocuous tweaks to policy guidance are actually huge. For example, at one point in a 'version' not so long ago it appears that the guidance on 'what happens if your sponsor has his license revoked' stated that you would have 60 days (or less if less left on your visa) to either leave the Uk or find a new sponsor. Now it does not mention finding a new sponsor, just that you 'may wish to make a further application for leave during this time.' However, it does not tell us how to make the application in these sorts of circumstances. I cannot find a form anywhere which would allow him to state his case and there is no email address. As I said, we have sent a letter, but have had no response at all. He does not want to be an over-stayer in any way. He has always abided by the restrictions of his visa and has respected the immigration rules of the UK. We just want to make sure we handle this in the correct way.