Thanks Jay. I've already had two sessions in the tunnel, so I know what to expect now. The annoying thing is that now after 6 months they are sending me for scans to check out what was my original theory, which the GP promptly disregarded with a patronising smirk. On the bright side, I've had all manner of cancers and other ailments ruled out, and know that there are various parts of my anatomy in fine working order despite 25 years as a smoker, and subjecting myself to all manner of other noxious substances and physical strains due to work and other pursuits. Hopefully this time they'll find something useful.
Toobfreak, point taken and duly noted. As mentioned before, I only used these jars as they were what I already had in. The bonus is that as each tin fills two jars, each jar will be opened half as often.