The banks website seems to be at https://www.metrobankonline.co.uk/ .. but Chrome says the SSL certificate is signed by an unknown authority, who claims to be VeriSign.
Additionally, the server is open to prefix attacks.
For a bank, that's a pretty miserable state of affairs.
This sounds, uh, weird. Got a link to more information? I'd like to see the rationale for having the browser subvert misconfigured servers; this would seem to undermine the already precarious SSL state we're in.
This is pretty much standard browser behaviour I'm afraid. One of the many unfortunate realities of the web.
I'd expect VeriSign to be on top of this.