[Organisational Audit] Can't edit question 5.3

[mbarton]

django-1   | ValueError: The OrganisationalAuditSubmission could not be changed because the data didn't validate.

<ul class="errorlist"><li>S05WhoProvidesSpecialistAdvice<ul class="errorlist"><li>Select a valid choice. 1 is not one of the available choices.</li></ul></li></ul>

I suspect this broke in #1065 when the field changed to a TextField but the values remained integers