Re: I'm with Google here...
According to http://hub.unlock.org.uk/knowledgebase/a-simple-guide-to-the-roa/
"The Rehabilitation of Offenders Act 1974 gives people with spent convictions and cautions the right not to disclose them when applying for most jobs, and buying insurance."
It doesn't indicate that a potential employer can't turn you down on the basis of a previous conviction they read about in an old newspaper or via a Google search.
That's not the same as your post:
"... that there are circumstances in which certain offences can't be considered ... on a job application ten years later."
I think it would be relevant if you get a job and then your employer later finds out about a spent conviction and decides to dismiss you because of that. e.g. you have a job as an accounts clerk and the managing director finds out about your 10 year old weed possession conviction and sacks you.