Regen using cheap fuel asda/tesco occurred at 80miles, but using shell/pb premium diesel regen round about 150 miles, and lighter blue smoke so premium diesel recommended (now at 145 miles/ 80% dpf clogged) and i just drove up and down the motorway and nothing happened??? Pre cat was uo to just over 400 deg and dpf sat at around 300 deg after around 20 miles of driving but no regen so far.