Guys; some extremely useful posts here which I've missed as I don't seem to get email when posts are added to the thread I started!!
I THOUGHT there was a thread somewhere discussing the heavy duty connection from the front to the back but couldn't find it. Thanks for a) suggesting there was one and b) finding it
BUT, sounding more clueless than I really am; where is that box that you unclip and find the connection. I can't make it out from the photo ...
Julian