What to do with ugly rear area?

[dmsims]

House is built on a hill with a small flat (north facing) concrete strip before garden retaining walls:

There is no drainage on the concrete but there are 2 manhole covers (fed by drains from the house side)

Originally the concrete slab was touching the render on the house side and was too high (the DPC was 8 inches down) so I cut a channel and filled with cobbles

I want to improve the look and drainage of this area but I am a bit worried that the horizontal slab might be helping to keep the garden walls upright

What further investigations can I do (or who do I engage professionally) to see if the slab can be taken up ?

Edited by dmsims on Monday 6th May 20:00

[dmsims]

Thread update:

Bought some Pliolite Masonry paint - as ever prep took 20 times longer than actual painting





Started pressure washing the concrete with a very old Karcher 330 which blew up spectacularly. That was replaced with a K4 which was much better with a Cone pattern attachment. Had to use a wet vac to pick up all the detritus.



Got a load of decking samples but we are also considering stone resin (no vehicle traffic)