The good news is that we're ticking off the things contribution to the damp.
Time to rent a big old drill to dig out the rest of the path and lay something a bit more porous, strip the rest of the cement render off and slap on some proper lime render.
No dpc = lime mortar so, good that you know OPC has no place here.
That de-rendered brickwork looks pretty good to me.
Good enough not to bother re-rendering? Point up with lime putty?
That copper thing.. is that maybe an anti slug measure?
The good news is that we're ticking off the things contribution to the damp.
Time to rent a big old drill to dig out the rest of the path and lay something a bit more porous, strip the rest of the cement render off and slap on some proper lime render.