I decided to have a go at disabling the computer height adjuster, so 4 screws off and the hood came off, and I removed the sort of flat PC wire with a red plastic connector at the end from the PCB It's the one on the left hand side of the PCB (facing the vacuum head from the front)
Just to make sure the brush was at it's lowest height, I ran the vac with the head away from the floor till the "down" light stopped, so I was sure.
Assembled it and it works great! I love it, it digs into carpets nicely, so satisfying
Only thing is the front indication lights don't work which doesn't bother me but if I was to sell it all I need to do is just connect the wire back on