Multiecuscan connected and solved the issue. (I have got the Gendan multiplex plug which looks reasonably nicely made too!)

Turns out that P0521 is Fiat-speak for the oil service warning light so there were in-fact no other problems!

(Bit naughty of fiat making a generic OBD code into a fiat specific issue and then making a "service warning light" into a fault issue that requires specialist equipment to clear!. )

I somehow suspected this but wanted to know if there was another oil sensor on the engine other than the "Obvious" oil pressure one.

Anyway. All sorted now!