Thanks Butcher, Ive emailed them for a quote for 1/4"x4"x12"
Today I finnished the gpu block. The base is almost perfectly flat, spent about an hour lapping to 1500 grit then I pollished it with silvo. I tryed to take a pic of the finnish but it was too shiny and shows half of my monitor.
It was leak tested under full flow of mains water from bath tap for 5 mins and didnt passed. I might paint the plastic top blue to get rid of the green pen by the barbs. Ill probably put it back on gfx card later this week.
Also a pic of my new heatercore with the old one. Spent the morning cleaning that up.