Slightly off topic, but why not make your own cheekpiece? On an 1813* the wood is held onto the metal bracket with two wood screws. It's a doddle to remove it, and screw on a piece of softwood that''s about the right size and shape. Cut or sand that to shape and call your uncle Robert. You even get lateral adjustment by how far across the bracket you screw on the new wood.
*And any Supermatch using that spring-loaded cheekpiece - 1413 (from 1972/3), 1613, 1813, and 1913 (until at least 93), and the 11 series of Prone-only rifles.