msm, I don’t have any experience of LCY (my experience is with ABZ, LHR, MAD and GRX - Granada) but here are a few tips, based on travelling with my Mum, who needs a wheelchair for longer distances and who can’t handle steps.

Per your last post, BA already has details in their system. Make sure they also have the wheelchair dimensions, weight and whether it has batteries or not. It is BA’s responsibility to pass your needs onto the airport – typically it is not the airline that directly provides the service.

Call the airport (LCY, not BA) in advance (I usually do it the day before) to see that BA has passed on the requirements to whoever handles things at the airport. If necessary repeat your needs.

LCY appears to have comprehensive info (“PRM & Special Assistance”) on their website, including a phone number to use.

We are used to the Ambulift (a bit like the vehicle they use to load the food carts on board), which is pretty straightforward in use. However at LCY they say they use the “S-Max Aviation Aircraft Stair Climber”. We have used this once at GRX (no air bridges) to board a small regional jet. You can paste that name into YouTube to see how it works. My Mum was petrified, so you may want to advise your gran in advance.

Make sure your gran and carer arrive with plenty of time to spare – in most cases things have gone smoothly, but they do take longer than usual.

Good Luck!