Schaukis:

I'm thinking the .338-06 is the answer. A 75mm case will not fit into the 95 action I don't believe. You might even be able to have the original '06 M95 barrel rebored.

I think you will have some trouble getting much better than .30-06 performance out of the 95 action. Case stretching will probably limit case life dramatically.

Where are you getting a 95 in UK? Original Winchester or Browning reproduction?

Browning made some long action BLR's. I'm not sure if they still do. The original was heavy, but later models had aluminium receivers. They handled heavy magnum catridges like the .300 Win Mag.