Caddy 1.6d won't start

Hi all new here had loads of caddy's over the years never had a problem with a diesel one before but this one won't start , was running well but had some work done due to these being a hobby it's been stood over a year and wouldn't start but a bit of tinkering it started but was hard to start so figured at least it's running i'll Take it to some one to have a look at once I mot'd it but now it won't start at all I tried all the obvious stuff , I'm kinda thinking it may need more experienced eyes being cast over it and here lies the problem who to use?? I can't drive it any where and who would any one recommend as a good old school diesel mechanic in Berkshire/ Heathrow area?? Most now a days seem to rely on plugging there laptop in and going from there so I'd prefer someone with experience of old vw's, thanks in advance for any advice

glow plugs or air in the clear line, or a fuel stop solenoid are the usual suspects.

Check the fuse for hte glow plugs good/bad is there 12V on both sides of the fuse with the ignition on?  yes, then the glow plugs are next.

No replace the fuse.

Glow plugs.
Remove the number 3 and 4 GP. (easiest to get to)

Short the GP against the battery that is the nut part is grounded to the negative post the threaded top screw is on the Positive.  (HOLD WITH PLIERS) they shoudl get red hot in 7-15 seconds, if they don't then replace all 4 as they go bad one at a time usually the 7 second ones go out after 1-1/2 years at least my 7 seconds one did, I carried one spare in the glove box and the 2 wrenches or sockets (deep well 1/4 drive) that it takes to remove one.  

1 GP you can go, no GP you can't go.

the clear fuel line that runs from the filter to the IP should not have any air in it (bubbles) if you see bubbles then the direction of the flw indicates where the air is bleeding in from Filter or IP.

crush washers on the banjo bolts on the ip and the filter leak if re-used without reconditioning them prior.

to recondition, then you clean them shiny and smooth
then hold over a flame till they change from shiny to dull

bubbles that travel from the filter to the it means that the filter or hose is leaking can be at the tank.

bubbles that go from the ip to the filter indicates that the issue us a front seal on the ip or one of the returns to the tank may be bad.

Stop solenoids can get gummy and need to be removed to clean them.