Should have updated this sooner, but anyway, the good news is the head doesn't seem cracked and there are no signs of any kind of gasket failure. However, I haven't set my hopes too high because I know in time the symptoms can show more...Only time will tell now!
Only problem I'm having now is a little bit of a issue starting, she takes about 5 seconds of cranking, if not more, to catch and start. I think I've narrowed the problem down to air in the line as I put a clear line in the return line and found small bubbles in it, should this line be filled with solid fuel? I'm assuming so. Tomorrow I will run her directly off a bottle bypassing the primer pump and tank and see if that makes any difference.
Once started she drives fine, idles smooth and sounds great. If I switch her off and back on again within 10 seconds it'll only take a couple cranks, maybe once to start. However the longer I leave it for, 1 minute + it takes longer. None of this changes whether the engine is warm or cold. Question - should the primer pump stay rock hard when the engine is running?