Barry
We have had the exact same problem with fitting the wheelchair into our Q3.
However, we have found the issue is all the boots are different in both size and depth, for example a Seat Alteca (same size boot as our q3 has a sunken floor and the wheelchair fits into it well)
We looked at 7 seaters like the Kodiaq, Tiguan Allspace and Seat Tarraco to see if it was practical to run it in 5 seat mode and have more space for the wheelchair.
In the end we ordered a RAV4 as the boot is huge.
Whats on your shortlist?
adam