Thanks for your suggestions, links and offers of parts guys.
I've been opening and shutting my boot manually [using the right end of the lid] quite a few times since it played up last week and the motor never 'clunked' [and I've obviously had the DIS display showing the pictorial red 'boot is not closed' image].
But here's a funny thing; I shut it earlier to day and realised five seconds later that I'd forgotten my laptop. But I couldn't open the boot - it was locked tight.
But then I tried the latch; the motor made a noise and the boot motored up and when I pushed the lid button it motored down and locked.
So now it works but I guess it will play up again and I'll need the diagrams and or parts you offered.
Keep you posted ...
Thanks - JUlian