Did they mention DBS - or did it just appear suddenly?
it isnt an auto-bar ( DBS that is)
and so you should be given a chance to make representation - once they inform you they are 'minded' to put you on the DBS list
and the reps should be
1) I am not working with children
2) there is no harm
3) nor danger of it
so listing is inappropriate
https://www.gov.uk/government/publications/dbs-guidance-leaflets
and yes amaxingly today someone has asked me to help make representations....
if any one is reading this as a regular ABer and has an IQ greater than 80, BAILII has the leading cases - AB v DBS and SV v DBS ( no I am not joking). Bit of a turgid read unless of course , you then have to write an essay ....