G'day, Nigel, and welcome to the forum. Glad you found your way to us.
Unfortunately, we run into a problem with export laws when we try to send gun parts or accesories outside the US. Seems everyone is worried about us evil Yanks arming the world and leading you astray from the pure and simple life.
Since you DO have a slide stop, a possible route would be to have IT Parkerized. Among other companies, there are these folks that MAY be able to recieve a part from you for refinishing, and return it to you-
The Shooters Roost, Inc. est. 2002
2304 Timberleaf Circle
Ingleside, TX 78362
TOLL FREE: 1-855-USE-TSRI (855-873-8774) | FAX 1-888-484-3765
You can also try contacting via their website Numrich- at gunpartscorp.com While they do not SHOW have parkerized sldie stops in stock, they frequently have the odd part here and there that is not listed.