Thanks very much for your speedy reply. A refreshing change from the usual forum ignore!
I am not quite sure what you mean by unchecking "wifi optimisation" in settings, where would I find such a thing to uncheck? I don't see it. If I can't fix the youtube problem it sort of rubs the gloss off a bit.
The other small problem is my inability to send emails using my own server (talktalk). I have been forced to use gmail which has - for me - a very unfriendly interface. The outgoing port is set at 587 and will not change, and I think that may be the problem. Any ideas?
Once again that for the response.