There is an issue if the WCHR comes out the hold with a baggage tag on it.
I won't go into the ins and outs of it but if they hand over the chair at the door there are issues with DOT regulations in UK.
As for SSR's yes they still exist and arrive at the handler who then passes them onto the terminal ops...
Crew then say again to ground handling when they are in bound what specials they have... Which again is passed onto terminal ops. I have even had ramp ops record the call to the terminal ops to prove they passed it on...
Makes zero difference with some airports. And its not just the UK you can wait hours in Hamburg for an ambulift. Raining forget it until the rain stops. Even had one punter with a missing leg and half the other leg gone, get off with his mates swinging between them because "its raining we will be here for hours waiting" he was right as well, we forgot to say anything when he was gone and it turned up 180 mins after arrival just as we were starting engines 30 mins late due to bus stupidity. And the bloke driving it had the cheek to get very upset and file a report to the company about wasting his time even though they had the SSR on departure and we spoke to ground ops 30 mins before arrival which meant it turn up 1:30 hours after scheduled arrival.