XJ6 S3 Expansion tank

Are there any alternatives for the expansion tank that could be used in place of the factory brown plastic expansion tank on the s3? Maybe something could be use from another manufacturer and modified to fit?
Current unit has a small leak, and as far as I know cannot be repaired. There was someone in Australia making stainless version but not available anymore.
Don’t really want to pay $470 for a new plastic one.

Depends a bit on the leak site, Zenith - but it is subjected to coolant pressure…so…

You could try and source a used unit, You could look for alternatives, but they would need the same configuration as the original one. Vent hoses in and out and cap configured for around 15 psi…

xj6 85 Sov Europe (UK/NZ)