Thanks for the info regarding the wheel not fitting with the low setting of the boot.
For my purposes, with all the mobility equipment I have to carry and the wheelchair or scooter, it is easier for me to have the boot floor in the high position whch gives me a flat floor plus room to load some additional equipment ie manual wheelchair motor option under the boot floor. I also have 2 suitcases that are a perfect fit standing on end on either side of the boot in the raised position leaving me room in the middle for the rest of our gear. The B is spot on for size for all our equipment. Having had the 2 puntures I have had to carry already the normal size wheels in the boot in the raised position.