I'd been suspicious for a long time. The Google Talk in Gmail and the Gmail Clips updates seemed to have been rolled out to US users, and yet I didn't know anyone who had had the updates. So, when a friend told me he'd managed to get the updates by changing the language setting from English UK to English US, I wasn't very surprised.
Now I've got the updates, and I can finally say they're good! I am seriously annoyed with Google though, for blatant discrimination against UK users. There's no possible reason for it, other than probably some Googler forgetting about us. I hope, in future, that Google will not behave in such an irritating way, because if they do this on a larger scale, with a bigger improvement (for example, not making GDrive available) then there could be a lot of grumpy UK users. And we're very good at being grumpy! (Only joking, we're nice really!)