There have been a couple of threads recently in which people have (a) placed a renault capsule directly in the top hose or (b) cut the top hose and placed a manufactured inline thermostat in the gap.
Not that I have an issue at the moment but planning for the future; what Renault 5 serial number is the one that'll fit within the hose if you know Neil please? Is it this one by any chance -
https://www.dmgrs.co.uk/products/rover-75-mg-zt-cdti-inline-thermostat-89-degrees - although the temp rating is different. Also I know that many in the 75 / ZT community don't bother removing the original thermostat as they're normally stuck open so is this essential for the coupe? On a general note why on earth did they stop producing them as they're available for all other coupe marques ..