Need a new engine thermostat and they are out of production.

What do you think I should do?

I could phone round everywhere but the likelihood of finding someone with one sat on the shelf is pretty small - Mangoletsi (UK Alfa dealers) told me that eper says its unique to the Q4

65-70C engine on the motorway isn't all that bad but its certainly not right.

Any help or suggestions?

Cheers
Jack