Why haven't they altered the page title to "ernie plasterer manchester"?
1) User searched for it.
2) It looks like they are present as anchor text to google.co.uk.
But those words are not present on page, and that could be one reason the title might not have been rewritten.
Yet they rank google.co.uk for that search because someone felt it is a page about "ernie plasterer manchester"! It looks like they trust those third parties (who link) more than the page owner or themselves (in this case google.co.uk) now!
If google.co.uk can be gamed, why not lesser mortals like us?