Hi,
I'd just keep pestering them, I got one from using that link, a very helpful guy (Andy somthingorother) helped me out. Maybe they are on holiday or just busy, who knows. You could always try calling them if you can find a number for their sales dept....
You could also try taking the reg into a welding supplies shop they may have something that will be suitable or put you onto someone who has, I'm sure its probably a pretty standard piece of kit used the world over.
Maybe even try a scuba diving supplier, they must also use high pressure gauges on their kit.
Regards, Chris.