O-D no problem. Writing stuff on the internet can sometimes be read in different ways. I think the Bowhill crash memorial was something Buccleuch Estates did themselves, so if manta was looking for help, that might be a place to look to. The guy I spoke to was really helpful.
Dug out the O.S. map and had a look, and tied it in with Bing maps. Stock Hill itself is a strip of land surrounded by forest, but bing maps shows a lot of harvesting has been done in there, with the attendant forest tracks. If there are no locked barriers across these, then it may be possible to drive up pretty close. Also noticed it may be possible to get in there from the Craikhope Outdoor Centre area. I do know there are barriers that are often locked on that route though.
Manta, when I visited the Bowhill site, you would be surprised to find there had been a crash there. It was all grown over, and apart from looking a little different from the immediate area, it was pretty natural looking. I can only imagine the same would be true on Stock Hill.
I might try and visit the site in better weather, but if you have any luck locating the site Manta, let me know. I notice you live in Hawick also.