are you sure they are scratches and not cracks, if in doubt, i would exchange that head for another, the "VM specialist " ( 01246 455350) will sell you a exchange overhauled head at a reasonable price, they rebuilt an engine for me for my second 2.5TD XJ at a very reasonable price, i learned that if you have a 2.5TD XJ, and you want to keep it, start by getting the engine overhauled by them, then you will have no further problems for years to come.
Hi Frosty i cleaned up the cylinder heads and noticed a few scratches on the surface of the head where i think the leak was coming from. i've attached a few pics, could these be big enough to cause the leak?
I bent a spanner and undid the nut one flange at a time, very time consuming. once loose 1/4 drive extensions and sockets with universal joints is another option