Data on actual numbers of mortgage taken out are available from the Council of Mortgage Lenders (CML). However they are only available for the United Kingdom as a whole.
The Council of Mortgage Lenders latest press release on this is on their website at:
http://www.cml.org.uk/cml/media/press/2218
The CML data on mortgage lending are no longer freely available from their website. For detailed time series information members of the public can request to subscribe to CML to obtain access to a restricted website.