:When much younger (about 9ish maybe?) i saw huge (huge - ie dozens per square metre!) numbers of these frogs in a pond in a holiday resort in torquay! I am 99.9% they were xenopus.
It's quite possible that there have been loads of releases of Xenopus, as there used to be thousands of them kept in hospitals. I don't think there have been any records of breeding in the wild apart from the two I mentioned, though.