re a London Rd side ramp.
Well the Victorians had one and it was a gentle slope.
I guess the engineers were a lot smarter back then.

re the fraudulent canal wall.
Of course the green tablets of stone do not claim this wall is original. It says this brick wall is on the site of the first canal wall.

Technically, the first 'canal' brick wall indeed was built here .... by the rail company as they filled the canal in (!!!) - leaving just a narrow strip along side Davids Rd and around.
There is no documentation to suggest the real working canal, the Croydon canal, was width restricted along here and so its eastern side clay wall (banks) would have been further east.

As the Davids Rd area was developed later than Perry Vale, my guess is that the PV wall would have been built first by the rail company.

Either way, I think that some of that PV wall is original, and it should not be allowed to disintegrate under the worst management for 170 years.