Did it!! Excellent video andyb2000 thanks! I found out that the thermostat I bought was actually mis-labelled in the database and was for an earlier voyager variant. I didn't fancy waiting for 2 weeks for delivery of the ebay thermostat that andy mentioned in his youtube notes so I did a little research on similar types. I picked up a thermostat for a 1992 Renault Clio 1.1 Engine code C1E700. It was about £8. It didn't have the same housing as the one Andy used, but the disc type. I had do do a fair bit of filing to reduce the diameter. It works a treat! Thanks all for your help.