Just an update.
Just got the car back yesturday.
All checked out fine.
Head was tested along with the head gasket both fine.
Had a compression test, come out excellent.
The cooler was leaking slightly but leaking oil OUT not in, but that has been fixed.
The little scum / oily film has been mainly put down to it being a new motor and during the rebuild may have got some in there along the lines.
So all in all, its all good. Flushed the radiator etc out for me to and topped up with coolent no charge, long story short im a happy man!