Will be at Knockhill on Friday with Bro and Son doing a Seat Saloon car Track Experience the one I Won at GOTC'S then heading South to East Mids, So wots the best/fastest route down.
The more direct route would probably be Motorway to Edinburgh then the city bypass to the A1. The bypass can be a pain between 3-6pm due to traffic and the A1 is full of speed cameras as far as I know.
The other route would be kincardine bridge heading for the M73/M74 then M6 down to Stoke on trent then back over to East midlands. Faster speeds very few cameras. The A80 can be a pain around 4-6pm. There's road works on the M73/M74 junction which may hold you up for 15mins. Total journey time 5.5-6 hrs.
If it was me I'd take the M74/M6 option if your in a hurry.