CRB Checks

We are currently looking into the requirement for CRB checking for some of our site engineers but we are not 100% sure if we will require this.

We are a company who will occassionally (and I have to highlight that it will only be occassionally) send engineers out to schools or attend calls to social housing where they may come across and work in close proximity to children (who a lot of the time will be running around semi-naked!). The concern from some of our engineers is that they feel vulnerable and worry that they are not protected as much as they could be if there were to be an accusation from someone at these sites.

Do we need to get CRB clearance for these engineers before they can go out to these sites as they will not be working directly with children?

We also work with 'service partners' who are linked to our company and will attend site on our behalf if we do not have the resource to do it ourselves. They are not directly employed by our company but will almost represent us when out on site. If CRB checks are required for our own engineers, would our responsibility for CRB checking extend to these service partners also or would they, as individual companies, be responsible for this?

If there is anybody who currently works for an organisation where engineers are sent out to social housing (perhaps British Gas or other utility companies) to perform maintenance checks on equipment, it would be great to hear what checks you complete and if you carry out CRB checking.