OK, I have already done this the hard way, just a few weeks ago to
decorate the stairs. Then I disconnected the rail from the brackets and
lifted the two rail sections (straight run up the stairs) over with the
chair still attached leaving the lower brackets in place. It wasn't an
easy job to lift it and move it across and refit due to the sheer
weight of it, but I couldn't see an easy way to lift the chair off the
track at the time.

Now I want to change the stair carpet and the lower part of the
brackets are fixed to the stairs through the carpet, each bracket has
four large screws into the wood.

This time, I am thinking - remove one of the two sections of track, and
run the chair off the end of the track. My original assumption was that
the chair could be dropped onto the track anywhere, then just have some
sort of bottom retaining clamp fitted.

I have spoken to Stannah, who are not very helpful, quoting Elphin
safety/ the world will stop spinning etc., they will remove for a fee
and reinstall for a fee etc...

Anyone know for sure the process please?