You really need to try and pin down the names and ages of the children. Is there anybody you can speak to who can remember the family?
Then although it's not an easy job you can search the birth and marriage indexes online at
www.ancestry.co.uk but don't search the database, you need to choose the top option and search the images since as recent as these births and marriage might be, they are probably not yet transcribed.
Births after 1912 at least have the mother's maiden name given on the indexes as well as their surname which gives you some help in finding them.
It's probably worth starting your search for the marriage somewhere just before 1927 and working forward until you find her name and then when you have the reference number, check for Harold and if the reference matches, bingo!
Hope this helps a bit.