https://www.ebay.co.uk/itm/Renault-21-S ... 2998341177https://www.ebay.co.uk/itm/Renault-21-S ... 2998342802The motors weren't listed separately and I haven't been able to find a part number, but they are also used on ren 21, 25 and probably other similar aged cars. The mechanisms above have the correct motor, but they are handed so you will the pair ...its the side the drive comes out that makes the difference.
watch for damaged mounting clips on the motor where they clip to the mechanism.
Ideally the whole regulator will need to be cleaned, the cable taken out and cleaned and the whole thing lubricated. The motors themselves are very simple and can be dismantled and lubricated. I got mine working by doing that, but you need a water proofing spray coating to restore the water sealing afterwards.
cheers
lee