Okie dok, It was the slightest spark no burn marks on the board and all components seem visually intact. I had the probe on CN5 ground pin and was navigating left with my positive lead I managed to get just the +5v reading and that's about it. I think your suggestion makes sense I've touched something too close across these circuits and as a result bang.
These are the components that got taken out, all were on the 68,-98 and -110 lines, so looking at schematics running down the -98 line first hit was TR6 D10,D9 and TR3 (but i assume the 68vdc took TR3) they all registered as shorts.
-110 took out TR4, D11 and R10 is also out, again all shorts and on the 68v as mentioned above TR3 and R11 are both out. I haven't looked at caps c12,13 or 16, not sure if they'd also be gone again visually they don't look cooked R16 is also below tolerance 1.5k im getting sub 1.2k so could just be a little old, all else apart for said caps in question seem to be intact. Ive left the 12volt line alone as mentioned the VR seems to be intact ill run some voltages across to confirm but continuity didn't show any contact between the legs. To the best of my ability all else seems to be within their relevant range levels.
In relation to pictures happy to upload ill take a few on the mobile and get them across some stage tomorrow for you to peruse if you still like once you've compared notes, hope this clarifies a little but again your above suggestion makes sense obviously somehow Ive grounded a line and taken out the above 3. frunch