There are a number of sources out there, it just depends on your budget and what you're actually searching for. The easiest solution would probably be the Warrior Assault System Universal Pistol Holster which would have the added benefit of being compatible with almost any future pistol purchases. While this isn't necessarily a cheap option it is hard wearing, superb quality and highly adaptable.
As an alternative option you could go down the route of having a custom Kydex holster made, there are a number of companies in the UK who can produce these.
Finally, you could always look for a leather holster from the States such as those from Galco.