Hi David,
Just some thoughts...
Have you looked into getting your Grandfathers Military service record from the MOD?
£30 and a bit of a wait but could be well worth a read!
http://www.veterans-uk.info/service_records/service_records....I did a quick search online.There was a 29th BMH in Hannover from 1945 - 1950 according to this site
http://www.scarletfinders.co.uk/133.htmlYou could also try posting your query on the WWll board, there are many knowledgeable contributors there who might be able to help.
http://boards.ancestry.co.uk/topics.Military.wwii/mb.ashxDon`t expect to find official records online from this era. They haven`t been transcribed.
Hope this helps!
Jacki