For the price of a skim i would do i for peace of mind its only about 30 quid.
If you are iffy about doing your dads car tunnie make sure you tell him the price a garage would charge which is around the £500 mark and if it was VX Bah It could be a million pounds.
As long as you take your time there is not alot that can go wrong its just time consuming but with james helpping out it will be a days work tops for the both of you.
Dont forget when removing the head there is a bracket that gos from the bottom of the intake manifold to the engine block the numpty who did my head gasket snapped this bolt off in the engine block and left the bracket on it took me ages to find out what the ringing noise was when driving it was the bracket tapping against the engine block but the noise was traveling up the bracket (mount) into the throttle body.
Since i cant drill the snapped bolt out i had to remove the bracket (mount) from the intake manifold to the engine block, And i cant go back to the guy who did as it took me 7 months to track it down

and he will just say it had nothing to do with me,