What is the website that...

[BecauseReasons]

...lists the popularity of British baby names called? Something to do with green or a glen, I think?

names.darkergreen.com

But there are lots of others. behind the name.com, or you can look on the ONS website.

Thanks, I have used the ONS before but found it a faff to look beyond the top 100.

Fair enough.

Behindthename.com, that was supposed to say. Useful if you want other countries too.