Re: Sounds like many sites will publish enough hints
But it's a bit awkward explaining the 2 year gap in the CV - either admit you were breaking rocks on Dartmoor or lie and claim you were an MI6 agent working in Bolivia - but can't talk about it. I suppose you could try "Government work".
The principle is tricky, as noted by an earlier comment. If someone is reformed, with or without a conviction being 'spent' and you know about it, then you can let them do the job, but with a watchful eye - or not - you could just trust them. If they are reformed the most watchful eye will probably be their own. But possibly avoid employing a multiple arsonist in a match factory.
Some years ago I lived in a village where there was also an ex-sex offender. Everyone knew, so no problem. Life moves on. But some people won't let life move on.