Well I finally got to the bottom of my intermittent starting problems. So it turns out that it was in fact failed glow plugs.
(I'm sure I posed this question to the MD back in November) so after a battery replacement, and several visits to MD (Thankful it's still under warranty) off it went to have the plugs removed/renewed.
Unfortunately during the replacement they've snapped one of the plugs in the head and it won't budge, so it's off with the head and a 3 week wait for me.
Now I've read a good article of what to look out for after head refit and it states:
The only additional work to be done after a head gasket replacement is an oil and filter change after 500 miles to insure no debris from the repair is circulating in the oil and a recheck of the ignition timing just to be sure. A close vigilance over the engine for the first week is advisable. The newest gaskets do NOT require retorque.
This sounds like good advice to me, but as always I would appreciate any advice from anyone who has had the misfortune to have had the head off, and their experience of the aftermath, and what to watch out for.
As always your comments, views and experiences would be greatly appreciated.
Steve