The Accuracy International thumb hole grip upgrade kits are available in fixed or folding and includes a thumbhole backstrap, rear end mouldings, and screws. For AT, will also fit AW and AWM. Fits new style stocksides only.
www.sportingservices.co.uk
You have to get the fixed version. Good news is it's the same skin as folder and has a score mark where you have to cut. I converted my tan and black thumbhole kits very easily. Cut a little long and then fine tune with rigid sanding block with fine sandpaper.
9 green kits in stock. Bunch of AI swag too, I picked up some stickers and a patch.
Edit: DO NOT call and ask if they ship to the US. They will say no but if you just do the order online they ship no problem. Myself and a bunch of others here have ordered from them without issue.