Basic Disclosure and standard CRB sound like the same thing.
CRB (Criminal Record Bureau) checks are now known as Disclosure & Barring Services (DBS) check.
A basic check will return any unspent convictions, cautions etc.
An enhanced check will be requested dependant on the job role eg if the job entails contact with children, vulnerable adults etc.
An enhanced check will involve a check of all offences committed and a check of the 'barring list' i.e certain offences such as sexual offences, being an ageing Radio 1 DJ etc etc
I would think, (but stand to be corrected) that Customer Ambasador / Gateline on a station will only require a basic check, I.e any convictions unspent according to the Rehabilitation of Offenders Act 1974.