You asked

I am trying to find information that splits down current UK population data on married and/or co-habiting couples by age band. I can find basic stats on numbers for the married and/or co-habiting couples, but no further 'splits'.

I am looking for the most recent (I presume 2011 census, although any projections would be helpful) data for:

Married/Civil Partnership/Co-habiting couples, drilled down into age groups/bands, layered with 'has dependent children'.

We said

You have requested information about the population of the UK under the Freedom of Information Act.

In response to your question: Special tabulations of data are available to order (subject to legal frameworks, disclosure control, resources and agreements of costs, where appropriate). Such enquiries should be made to: families@ons.gov.uk. We recommend that you contact the Families team directly in order to discuss your data requirements in more detail.

As this information is already available to you via this route ONS considers that S21(1) applies to this request and the information does not have to be supplied under the terms of the Freedom of Information Act. S21(1) is an absolute exemption and no consideration of the public interest test needs to be applied.

If you choose to contact the Families team they will be able to discuss your requirements with you, including the geographies and variables that are available, they will also be able to discuss any likely costs surrounding the production of the data that you have requested. They will be pleased to help you.