I once again urge you to read the Employment Statutory Code of Practice. Here's some highlights though:-
What the Act says 2.31
A person who is married or in a civil partnership has the protected characteristic of marriage and civil partnership.
16.62
It is particularly important to avoid irrelevant interview questions that relate to protected characteristics, as this could lead to discrimination under the Act. These could include, for example, questions about childcare arrangements, living arrangements or plans to get married or to have children. Where such information is volunteered, selectors should take particular care not to allow themselves to be influenced by that information. A woman is under no obligation to declare her pregnancy in a recruitment process. If she volunteers that information, it should not be taken into account in deciding her suitability for the job.
I'd also do what regulator said and go national. The national person is not going to be amused in the least. The local person may well be in on the act.