You could try this link:
Triumph Motorcycle Links
TT600. Nice choice of machine. Almost bought one.
Try the acetone in the keyhole H.A. It might need a few goes, but if you're careful it should work.
Check with Triumph to see if a lock barrel is available as a seperate part. You could drill it out and save the rest of the cap.
You're lucky they didn't put Armorall on your tyres. I saw the results of that a couple of times when I worked in a Suzuki dealership way back when
