This advice will probably better fit here...
For the low air time pilot, a low inversion usually means pretty rough conditions as the thermals are badly organised, and bouncing on that layer, so you get a mix of bullets and sink. I don't think you should fly at least till it is broken (or really early at sunrise...) even if you have a pretty tolerant glider, Gabriel showed us that even aDHV 1 or 1-2 can get a cravate after a collapse and engage into a spiral. Lucky he had enough height.
On a good thermal day, tehre is always some magic lift at Bakewell late arvo and I think this is teh timing you should head for (or at least after the inversion is broken).
An iversion is a layer of warmer air laying at a certain altitude which will block the thermals.
If you look at the baloon tracing of the day (usually released around 9am every day at http://slash.dotat.org/cgi-bin/atmos?loc=94610&latest=1
) you can see at the tracing of Sunday http://slash.dotat.org/cgi-bin/atmos?lo ... 0925230000
on the second graph that the curve is kind of a flat between 14 and 26C at a very low level (around 3000'), when after 26, the curve start climbing properly (inversion breaking). The forecast temperature of the day was 27 at Northam so it was quite unlikely the inversion would break before 1 or 2 pm, so good time for the novice to launch would have been after 3...
As far as article, not sure where to find it, (I only have a french translation of it) but Will Gadd also wrote a very good article about thermal flying. I think it was called "Thermals Hunter" or something like it. Probably a good idea to put the link here if somebody find it (it may be into Jerome Daoust bibliotheque...)