Pete,
Thanks for the interest. When I bought car (Jan) it absolutely refused to go into 3rd gear going up box, but sporadically engaged 3rd going down the box.
Stripped box completely then ran out of talent so Glocester Rd Gearboxes put it back together with new Synchros. Back in car, clutch refused to disengage fully (creeping forward with foot fully on clutch). Changed slave cylinder & seems improved, but now issue is that I can go up box & suddenly it won't go in to ANY gear. Have to bang it in to a gear, then will behave for a few minutes, then repeats issue again. So leaning more toward g/box related, but my experience too limited to know where to go with it next.
Still, looks good with the GT6 bonnet back on the Spitfire bodywork!!!