Ghengis, thanks for the link.......I've just registered to attend at Manch'.
Just an empirical observation, no data to back it up, but when I first set up camp in the Mt. Belzoni area, 34 years ago, thunderstorms were a frequent occurrence. Some of these were large and would often last for ages. Recently, the numbers seem to have declined and this has even been noticed by friends with no real interest in meteorology etc. So far this year, I only remember hearing thunder about two times. Could this be due to more vigorous circulation over The U.K., therefore not allowing so much Cb formation as in previous decades?