Need camshaft seal for Fiat 242 or Citroen C35 engine - where to buy?

[zippyfiat]

I need a camshaft seal for a gasoline version of Fiat 242 or Citroen C35 engine.  Both vans from the 70s/80s.

These engines turn in the opposite direction to a Fiat 131.  These engines are basically the same except for rotation.  I am building up a reverse rotation 131 engine using a camshaft and distributor from a 242.

The Fiat part number is 4321335 and was later superceded by 40002090.  The seal size is 52x30x7.

Does anyone know of any parts suppliers in Europe that might have engine seals for a Citroen C35 or Fiat 242?  Have spent many hours on Google and ebay all over the place trying to find just one source, but to no avail so far.  The language barrier in Europe doesn't help either.