Hi Richard,
Great question, often organisations are required undertake their own DBS checks meaning that as you rightly point out the process is duplicated multiple times. This is unfortunately par for the course in the sense that a DBS check is only a historical profiling of an individual, so School B could encounter problems if they relied on School A’s DBS certification, or indeed the teacher’s, if an issue arose between that certification and a new that School B should have carried out.
That said gaining your own Enhanced DBS certificate is no bad thing, you can find out more about doing this here:
https://musicteacher.kinsta.cloud/dbs-checks-music-teachers/
Interested in getting thoughts from other teachers about this as well – how have other people found this problem of needing multiple DBS Checks each school?