There are possibly older or off patent eCall cars that use 2/3G only I did see that there was some suggestion of killing off 2g sooner.I suspect quite a bit of the 2g network will be long gone by 2033 - some bits have already gone as some equipment is not being replaced when it fails. (It's not being made any more and the manufacturer no longer exists). AFAIK so far this is only a reduction in capacity, but I guess once the holes in coverage get big enough, some things will stop working.
Ofcom keeps sending out random updates on the subject (which I have unsubscribed from, but still get!)
Just did a quick search of a fairly recent one and came up with:
"In particular the Government is giving consideration to the requirements of key services
ahead of switch-off, including eCall and smart meters. "
Sadly, this does not fill me with much confidence, but maybe that's because I am a cynical old git...
Avanci seem to suggest 80-85% are compliant with the standards to still 15-20% who may not be using 4G, I think that is more likely to be the much older cars, usually before the standards are finally firmly settled. So by 2033 they may all be in scrap yards anyway?
The “official” switch off is 2033, then again we still have the analogue radio services fm am etc that we’re supposed to be switched off ages ago. I think they announce these things in the hope it will push people to update, encourage people to upgrade older tech but one thing that it’s going to massively affect is the million old people with a pay as you go Nokia 3110 they're had from new, and have no intention to update in case they have an emergency.