3puttssuck: Yep, it appears to be a faulty handset. It is now stuck in recovery mode and I spent an hour with Apple online chat trying to fix it without success. They suggested I return the handset to Vodafone for repair / replacement.
@3puttssuck I'd be insisting on a new replacement rather than repair (and not a refurbished replacement either), was obviously DOA but the kind of fault that just wasn't immediately obvious.
