The location of the cemetery needs clarification. It is the North Cemetery. The Postcode needs clarification. We visited yesterday with friends and had to go round and round to try to find it. Fortunately, we stopped by and asked a lady who was so kind to offer to lead us there by her car and we trailed after her. We were also touched by the eulogies of some of the graves stones nearby. Some we could still read and some faded away completely. It is worth to linger a bit longer to meditate on what were written, mostly from scripture.

I understand that this Headstone in the picture is a replacement/ replica of the original --which must have become badly weathered (look at the surrounding ones...)

You may be right, though as far as I'd remembered it was the original but just had been cleaned up 20/30 years ago and kept in good condition since. It's actually quite possible to make a grave stone look 'as new' - the same was done for FER's in the early 00's by members of the (now) PBCC.
Ten years and one month now, since I took those photos , and not been back since .. how time flies!

Just to spoil the fun of future Darby hunters, here is the precise location of Darby's gravestone:

https://w3w.co/gasp.energy.bravo