Looks like I have more clarity now. The more reasonably priced custom rifle stock makers that I contacted said no. Others the prices are just not worth my contacting. My brother-in-law repairs air rifles and has a box with loads of stocks and having taken the stock off to service the rifle (I have a few pages of typed A4 notes on the disassembly, checks and reassembly that I may post later), I took the stock and compared it to his collection. Most of them did not have enough meat to fit the park mechanism although he has given me one new HW 77 stock that it looks like I could use as a donor stock rout out and modify. Initially I have decided to strip back my RH91 stock as the beech stock is quite bland and having used some varnish remover to get the old coloured varnish off and given it a sand so that it is now a white wood, there is actually some quite interesting grain in the stock. So initially I think I will be using a Dremel to make some finger and thumb indentations once I have marked them to add interest. Then before I colour it (think I will go for a medium brown), ad as I cannot do chequerin, I will be doing some experiments with texturing on a piece of hardwood to see if it is worth marking out and texturing the grip.