This might be more appropriate in the Complaints forum. However, are TCD saying that you will be downgraded if your mum is USING her wheelchair or just if she wants to take it on to the flight?

I suspect you and TCD have your wires crossed. They probably think that she requires the wheelchair when on the flight and perhaps, for safety or space reasons (though you'd think there would be less space in coach), they have to put wheelchair-bound passengers on the lower deck. If they want to downgrade just for checking in a wheelchair, that's outrageous and surely illegal (sounds like discrimination to me)... again, unless the wheelchair will actually be carried on as hand luggage (for want of a better term). I still don't understand why they would downgrade you but it might be because you have to be in an exit seat or bulkhead seat and those are all booked out on the upper deck. However, they should have explained that so I would phone them again to ascertain the exact reasons behind the downgrade.

I also think that TCD/you may be working at cross purposes. The downgrade (to the lower deck of the B747) would be because they probably think that your mother is reliant on a wheelchair and like other airlines would not be able to put a passenger requiring wheelchair assistance on the upper deck of the aircraft. This is more to do with getting a wheelchair bound passenger up the stairs between the lower and upper decks.

Call them again and explain.

Have you thought about just using the wheelchairs/motorised buggies at each of the parks that can be rented?

Welcome to HT Yippee!

You'll find a dedicated TCD topic in the flights forum HERE

Pippy