The HS1-HS2 link would've been great, had HS1 been built to terminate at the underground King's Cross station that never ended up being built. As is it is, it doesn't really go together nicely. But also the bigger problem is with the immigration and security theatre required to go through the tunnel, meaning you either have to change trains or have all of that at every other station that the trains would call at in the UK, which isn't really feasible. If we could reduce (or remove) these requirements that would be great but we've been moving in the opposite direction.

That said, the main point of HS2 is to move the existing long distance services (which don't mesh well with slower trains, reducing capacity) off of our existing mainlines, creating a lot of capacity for more local and freight services across the country.

Wheelchair = luggage trolley.

The looks I'd get trolleying around my dear mum in her chair, absolutely laden with luggage or bags. I can only assume people thought I was some kind of monster doing that to an elderly lady, when in actual fact she was the one who would buy too much or insist on carrying it all.

Not that this would have helped in your case. IME trains are not wheelchair accessible. In theory they are, but when you turn up on the day, the lift's not working or you need to take 5 sets of stairs to get a connection, so that you end up having to take another train to a different station in the hope of their lift actually working, to take a cab to the station you were just at. Never again, basically.