At the risk of announcing myself as an idiot .... check your junk email folders. I've been solely using my iPhone for two weeks, which is only set up to view the inbox. Suddenly realised i should be more thorough and logged on through the internet. An invite from CTC had been sitting in the junk folder for a few days. A little odd given previous correspondence got through just fine.
Not my finest moment, but after hitting refresh 1000's of times during October, a little relieved!