Sorry for the late response folks, but I've been away until last night.
Thanks for all your comments, particularly about the ridge board. Now sorted....
I've spent this morning in the workshop and I've done some additions and alterations.
Here's the offending ridge board - or lack of it anyway!
A sketch done after the battle shows a wall directly in front of the Hospital at the same height as the escarpment. As the attackers were supposed to have breached the defences either side of this, I figured it must have been a good height. Also I reasoned that officers, being officers would like a nice flat area to have their 'Tiffin' and admire the view away from everyone else. So to give the rankers something to do they had the wall constructed. All my theory and probably a load of b*****ks, but I'm sticking with it......
I made the wall from a thin strip of polystyrene, stuck it in the middle section of the original escarpment, then dug at it with a small screwdriver and my finger nails to simulate a rough stone construction.
I also made a second, lower level escarpment either side of the wall for the Zulus to run up to reach the meelie bag wall (Bless!) out of a piece of 20mm scrap polystyrene cut down the middle and hacked at.
Left side....
Right side.
I slurried on some of the adhesive to tone in the front wall stones to match the escarpment colour and built up the top ground level to the wall using powdered adhesive.
I've also started to build up a bit more texture to the ground below the escarpment.
....and forming where the thin band of soil and turf would have broken away on the upper ground level due to the 'farsans' of feet!
A bit more ground work needed then I can start the painting and vegetation.
Cheers.
Ron