You can't.
Some possible solutions:
Nanny contacts a nanny agency and asks them if they can do an Enhanced CRB check.
Nanny registers with Ofsted (as part of the registration process, Ofsted does a check).
However... do consider what the point of this check actually is... we didn't have these checks 10 years ago. CRB Explained (history and the problems)
Why do you want this check, what will it actually tell you - and could you then use that information to deny them from working? It may tell you that they had lots of cautions for shop lifting as a teenager (when I was checking CRBs it was a common feature to see). That would not bar them from working with children.
Ask your nanny to sign a statement saying they have not got a criminal record. Someone may be able to come up with the wording for
such a statement.
Bichard Inquiry Report (PDF)
4.115
Under my proposal, an individual wishing to work with children or vulnerable adults, including in the voluntary sector, would apply to a central body for registration.
4.116
The central body would have access to all the information currently, or soon to be, available to the CRB: that is, PNC records, local intelligence, POCA, List 99, POVA, HM Customs and Excise, British Transport Police, NCIS, the National Crime Squad and the Scottish and Northern Ireland equivalents of
the PNC.
4.117
The central body would take a decision on the basis of the information above and notify the applicant. At that stage, no other employer, individual or institution would be informed. The applicant would have an opportunity to appeal against any refusal, either to the Care Standards Tribunal or some other appropriate independent body.
4.118
Under this system, employers would still decide whether or not a job required the postholder to be registered with the central body. If they decided the postholder did need to be registered, employers would be aware that the authorities knew of no reason why an applicant should not be employed to work with children or vulnerable adults. Employers would also retain the ultimate decision about whether or not to employ someone, using references and interviews.
~~~ End Quote ~~~
Copy and paste the above into a letter and send it to your MP. It is the recommendation of the Bichard Inquiry - yet Government still has not actioned it. In fact the current Government has put it (<a class="break-all" href="http://www.isa-gov.org.uk/" rel="nofollow" target="_blank">the ISA</a>) on hold.
The ISA was meant to start in July 2010 for people like Nannies. It would have enabled Nannies to be on a central register, which employers could access to check registration status.
Should that scheme be on hold? As a parent you are for some reason wanting your nanny to have a CRB check, so you would be in favour of the central registration scheme I presume... but why?
How does knowing any of this information about someone make things better?
Unless someone has been convicted of a crime against a child... then how does the information help you?
Interview nannies carefully, check references carefully. Rely on your instincts.