I found the contact us but its a web form no phone number. £40 is a lot for a bit of hardware, I would expect to be able to register on the forums with a bit more ease than that.
Browsers: SeaMonkey and Firefox. Never had any trouble with captchas in either of them unless they're from re-captcha who's standards have gone right down the pan.
Even the audio captcha was impossible to understand. I tried that multiple times. There is so much background hiss in it that you can't recognise anything.
As for David Cuartielles, you would think that he would have a valid email address especially as its listed as 'Technical Contact'.