secril_fd-interface is an issue with fast dormancy...its designed to save battery life, but only if your carrier supports it...
Just reading through again and highlighting what you said about whether my carrier supports fast dormancy.
That sounds interesting, how would I know if Three UK support it or not? I could contact them but I'm sure they would not admit to being the cause of the problem, and I suspect most of their staff in store/on the phone or online helpdesk would have no idea what I'm talking about and just tell me anything.
Is there a definitive way to find out whether or not this is supported?