The question about a criminal records was not on the application form and she was not asked about having a criminal record at interview.
She has to have a statard CRB for the job now what should she do?
Should she tell her new employer or wait until CRB comes back?

Im not 100 per cent sure but l think the standard check may not show a spent conviction. Go to the CRB website and see if you can find out. x

It will show - anything does. If she has not been asked or had to make a declaration she does not need to say anything until they ask when they receive CRB back. If she has declared none on any paperwork or told them she has none, she may be in trouble when it does come back as they will think she is untrustworthy from hiding the conviction.