Purge Valve

Hi. I would appreciate it if anyone could help with the following:-

I need a new purge valve for a Freelander 1.8 2003 but just cannot find anywhere that supplies them. The old valve is a Delco Remy 22431? valve. I cant find any purge valves that look like the one fitted (see pic). Is there an equivalent valve that I could buy and if so where. (in the UK).

Thanks in advance for any help.

regards

SP