Understood.
I'm sure others might have suggestions but here are 3 from me:
1. Since these are British graves, I wonder if the Commonwealth War Garves Commission might accept responsibility, and you might contact them. The cemetery is one of theirs, it seems:
www.cwgc.org/visit-us/find-cemeteries-me...klerksdorp-cemetery/
2. I think raising funds from volunteers/enthusiasts in South Africa is likely to be unproductive. You might want to open a discussion with Bert Gaffen to see what he suggests in terms of raising funds in the UK and how the funds should be channelled to get results. You could google him and you'll see he is on multiple social media accounts.
3. You might try to seek funds from the regimental associations in the UK of the units whose fallen men lie there.
I'm sure others will come along with suggestions soon.
Rob
