Myself and plenty of other instrument rated pilots would definitely pay for a 1-day course on how to interpret these (and other) diagrams. Do drop me a line if you know somebody who can do one, in southern UK somewhere.
Take a look at
http://www.lasham.org.uk/learning/met.asp. I went on this course a few months ago, and I now know more about soundings than I ever thought I'd need.
I think all the planned courses are full, but Lasham might be able to organise some more, and Matt might be able to cut down his material to a one day's worth, more suitable for power pilots.
Cheers,
David