The extended CRB check that you undergo for working with children may pick up the caution. Don't try to hide it, just get on and apply for the jobs. You presumably have a positve reference from your last boss. Also, is it going to be 'spent' soon? If two years have elapsed and you've not been in trouble, I think this will not then be live on the police database.
Look carefully at the wording of the form you fill out when applying, and if it only asks for convictions, then just keep shtumm about the caution. However if it asks about cautions don't lie on the form.