[stolfordtone]

Just a thought on the roof problem; I'm not sure whether this is a problem that has just developed or whether it's always been there, but are you aware that you have to keep your finger on the button for a good two or three seconds after the roof is down to stop the light flashing?
It's the same when putting it up, to make sure it's properly locked in.

I really hope this turns out to be a cheap 'fix' for you. You may not have a fault at all.

Can't help with the sat nav as mine doesn't have one.