On the Caroline affair itself, Jane Robins's book "The Trial of Queen Caroline" is pretty good.
The key differences between TTL and OTL are:
• Everything connected to the Caroline affair is happening about six weeks earlier.
• At this point IOTL, public unrest had already taken the form of demonstrations like the Manchester demonstration that ended in the Peterloo massacre, and the Radical War in Scotland. ITTL, the economy took longer to slow down and the pressure is still building.
• Charlotte Augusta is involved. And Talleyrand is definitely up to something, although I'm not saying what just yet.
Merci mille fois And given just what's transpired so far, I don't doubt it's a good read...
Edit: Damn, no luck at either the Orleans or Jefferson Parish libraries...
Edit 2: found it on Amazon cheap