Wirelessly posted (BlackBerry: BlackBerry8530/5.0.0.1030 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/417)

"Maybe go straight up to Scotland and start the trip up there, then EDI > CDG (LHR Stopover for 8 days), and return from CDG?"

Definitely worth considering. Note that BA offers service from EDI (and GLA, too) to LCY, in case LCY is a better airport for you when you head back to LON. So you should be able to do EDI/GLA-LCY (stopover) LHR-CDG/ORY as a Reward Flight Saver.