Well, we have been in this house for 10 years. Built by a builder, but so many flaws!
The quality of the mix of cement varies- either just sand+++ or so solid that you cannot drill a hole in it.
I would have built what amounts to two short walls out of 2 X 4's and used a piece of 3/4 cabinet grade plywood or laminated shelving board for a top. That way it's removable and strong enough
I am not quite clear what you mean (South African-2nd language)
It reads like this- is this what you have in mind?