Connelly sent me these instructions after ruling out some other issues. I was sceptical at first but it actually works!
Followed the instructions, took the boot out of the oven and by the time I re laced the boot it was cool enough to put my foot in. I did have a thin sock on just as a precaution. The issue that I had was the top of the carbon boot was placing a great deal of pressure just above the ankle on the outside. I use the round end of a screw driver to push this out. I had to heat the boot twice to get the best result but the issue is now gone.
@Brewski was on the right path. The cool thing is that by being able to mould the shell to your leg type/shape, you actually reduce the need to cant.
Thank you to all thise that posted suggestions. Special mention for Robyn Corl and the Engineers from Connelly who have been most helpful.