Mitsubishi's reply to my e-mail;
I'm afraid there are no plans to release this in the UK. The version on the advert is not a complete song - it is a 60 second adaptation commissioned by Mitsubishi New Zealand and performed in the studio by "Lineman". The advert has been used in New Zealand for some time - when we saw how good it was, they agreed that the UK could 'borrow' it.
So there you go.