A lot of disability discrimination is handled at a national rather than EU level, because EU law is pretty narrowly constrained by the treaties and the purpose of the EU.

In the UK, there's a "duty to make reasonable adjustments" if "a provision, criterion or practice [...] puts a disabled person at a substantial disadvantage" (s20 Equality Act 2010).

But there's quite a wide margin when it comes to what is or isn't a "reasonable" adjustment.

Lots of historic buildings are never going to be fully accessible without a massive rebuild project. The cost of retrofitting, say, the London Underground to be fully wheelchair accessible would easily reach into the tens of billions. (New capital projects tend to have accessibility baked in—so the DLR, built in the 80s, is extremely accessible, as is the renovated bits of the Jubilee Line, and Crossrail will be.)

The "reasonable adjustments" don't necessarily need to be providing physical access adjustments like ramps/lifts. For instance, when I was in university, one of the students on my course was in a wheelchair, and they relocated all lectures, tutorials and seminars he was in to ensure they were all in the rooms that were wheelchair accessible.

There is some EU legislation that tries to unify accessibility rules across the different countries though. https://ec.europa.eu/social/main.jsp?catId=1202