Hi T Gill and welcome again
I get the impression that these events may be quite recent.
Has your mum tried to see if her file exists with Social Services? If it does, there may be information in that.
Other than that, I would suggest getting hold of your grandmothers birth certificate. Her death certificate should have her place of birth as well as her date of birth as long as the informant knew what it was.
To order the certificate, you'll need to get the correct reference from somewhere like
www.freebmd.org.uk or a subscription site if you have paid to use ancestry or findmypast.
Her marriage cert to your grandfather should show her fathers name and you can use this information in conjunction with the the birth entry to find your great grandparents marriage and brothers and sisters she may have had, as long as they stayed in the same area and the names aren't too common.
Finding information about your Chinese grandfather may be difficult if all you know is his name and age at the time of their wedding. I know it's most probably a difficult subject to talk about, but do you know what happened to him? Did he die, did they divorce?
You could look at electoral registers to see how long they lived at an address but they won't be listed until they are 21. Most registers aren't online and you'll need an address to start with as they are compiled by constituency, ward and street address not by surname.
Hope this helps a bit.
Dawn
