Doughboy - I know little about the legal side of it, but I used to be involved in recruitment in the industry, and this sort of thing cropped up reasonably regularly. What you don't put on a CV cannot be considered, but if you're asked the question on an application form I respectfully suggest that you answer it candidly. Unless the convictions were for a major crime, or dishonesty and you want to be a beancounter, (although the 2 go together sometimes
), I would hope that the employer would consider all your plus points before taking the offences into consideration, if at all.
Best of luck.