Di,

Using Freebmd this looks like it could be the second marriage of your nan.

Marriages Jan-Mar 1932
Cutting John W, McDonnell Aylsham 4b 178
McDonnell Shiela, Cutting Aylsham 4b 178

FreeBMD has index of Births Marriages and Deaths from 1837 to about 1960.
http://freebmd.rootsweb.com/

Certificates cost £9.25 from here
http://www.gro.gov.uk/gro/content/certificates/

If you get the marriage certificate it should give you the age of the bride and the name of her father.

You can use Freebmd to see if the couple had any children.

Bryan