...I never did get round to fixing this strat up...UNTIL TODAY.
I noticed it lying in the corner of the room and decided to do something about it. I've put a 1mm plectrum in the neck pocket as a shim, and that got rid of the buzz; then i was free to use the action adjusting screws on the bridge to level out the saddles a bit more and it feels godly.
Only complaint i have is that the plectrum shim seems like a bit of a bodge. is there anyone that makes them professionally? if not can one of you guys (wez/jonathan/bob/anyone else) make me a simple maple shim to stick in there? PM me with quotes for prices...
Can you clarify where in the neck pocket you have put the shim/plectrum?
If it's under the heel of the neck then where exactly???
It certainly wont rescue an over-straight neck, but if it is at the trailing edge of the pocket it will have tilted the neck & raised the action somewhat and that will give you extra clearance and reduce buzzing but at the expense of your low action.
Actually I will assume that the above is what you have done as if the shim is at the body end of the cavity it will have tilted the neck the other way which would have lowered your action which certainly wont have helped the buzz situation....