Just thought I'd share an experience with you and hope it helps someone. My gauges started to not work no speedo, temp or revs, then an intermittent starting problem it would not catch then when left for a while then start. This then got worse but would only start with a jump.

I cleaned battery terminals and fuse connectors to no avail , got it home one night and it would not start at all. I noticed the preheater light was not coming on.

After much research I plumped for a realy 109 fault and ordered one from eBay second hand but tested for £6. To get to the relays you need to remove the panel with the fuse box in it it is the trim panel "uk"to the right of the steering column. Take fuse box cover off remove screws from box and two on the same face of fuses. Under steering to left side remove two screws , push in headlight selector and turn to side light to withdraw light switch , then work out the housing the final securing screw lives behind the housing I broke mine because I did not know it was there. Simply work the panel out a small amount of pulling should suffice. 

109 should be clearly numbered just pull it out and replace my replacement was smaller and went in with the number upside down. 

I turned the key started first time all gauges work, reassembled and after spending 2 hours freeing drums everything worked fine. I hope this helps anyone with the same problem.

Result mate