Drove it back home and used the Corsa instead,
Just been out and mopped up the spillings, started the engine and diesel is squirting from the injector up the thread of the connector boss, took it out and replaced the alloy washer, reduced the spray to a seep so I've coated the threads with silicone sealer to see it that will cure it but I think only an injector is going to be a complete cure.
This car is becoming a pain in the bum.