There was a subtle problem, the fix is that I've gone to your site config and changed the domain name setting from "abingdonhydro.org.uk" to "www.abingdonhydro.org.uk". i.e., the same but with the www.
The version without the www is having a redirect done on it by 123-reg, which is what was causing the problem (because Voice was redirecting to the non-www version, then 123-reg was redirecting back again in a loop!)
Telling Voice to use the version with the www means it all works fine.
Thanks
Voice Admin
A PS to the question above: the fix worked, for which thank you, would never have found it. However it led to a further mystery, that it worked with all browsers except Firefox. The solution turned out to be simple - Firefox was still looking at the old address, so it was solved by emptying the cache,
Richard