I presume this is a TD4?
There are a multitude of recent threads on here about TD4s not starting. Its probably easiest for you to have a scan through them than people writing the same stuff. Not sure if there's a 'sticky' thread (ones that always appear at the top of the thread list) - there should be if there isn't. Starters for 10, injection pump solenoid O ring, fuel lift pump (under rear wheel arch) and filter, fuel rail fuel pressure sensor harness, cam sensor pos crank sensor, injectors, ignition switch - they're the common reasons I believe.
As for the sunroof its probably the little plastic cog on the end of the motor up where the interior light is - the fix is to not use it and hope it doesn't leak. If you do want the roof to open, you could replace it (probably the whole motor and cog, then wait for it to break again and increase likelyhood of leaks. If you do try to fix it, check it first to make sure that is the problem before buying a replacement. I believe you have to take the sunroof surround off to get at it, there's probably a procedure described in the Rave workshop manual. There's info on downloading it here...
https://www.landyzone.co.uk/land-rover/rave-disk-maintenance-manual.260227/
