Well chaps, bought myself some 130grn TTSX for the 308 and under the guidance of some very experienced friends, we went about building up some test loads.
Shot last night and was happy with the results. Rifle/bullet combo seemed to really settle down towards the higher end of the charges.
Very happy as the rifle has been quite ammo fussy with factory loadings.
Right hand target top two groups being the best, 46.7 & 47 grains of N140.
Need to find a friendly person local to me with a chrono now

I'll go with the 47 grains. I'd think they'd probably be tighter if I let the barrel cool down more, had to kick on! ... and with a more accomplished rifle shot.
(The bottom right group of the first target had a proper flier, maybe neck tension or resizing was at fault, no case deformations afterwards)
.... and no I didn't use my truck tyre as the back stop

Suffice to say, the deep dark rabbit hole of reloading is beckoning!