I ended up getting one of the capillary oil temp gauges from John Cradock through ebay. Bid for a few before I finally got one. I steered clear of the water temp gauges due to the price and the reports I kept reading that they did not fit properly, but as has been pointed out it may work if routed differently.
I have sourced a series 3 electric water temp gauge for time being and my intention is to take my dead water and oil gauges to a local instrument restorer to bring back to life at some point in the future when I have money to throw about.
I also have a VDO electric gauge that will sit in one of the three 52mm holes as a backup gauge (or rather a more reliable gauge).
If you're looking for new bulbs for the instrument cluster I sourced modern fittings and replacements from here:
Electrical Miscellany Page 2

