Jochen - thanks for answering those questions for me.

With regard to my old Mk III unit running 3-1/63, I should have added that V22 is what I installed immediately before taking it out and fitting a Mk IV, and it's been sat here in my office waiting to go on eBay ever since.

From what you say about this update affecting only NAVI03 I'm not going to bother updating either of my units, they're at 3-1/63 and 4-1/00 so there's no point.

I'll remember the Mode2/Form1 issue for next time.

Thanks again.