Hi, I've managed to find a bit about them - my ancestor married Mary Stroh. My mum (born 1919) said that as a kid she was told never to mention that her grandma was German. John Peter Stroh, who had the shop, may have kept his name but after the war his sons seem to have changed their name to Shaw - there's a notice in the London Gazette dated 9th April 1920 for the name change of Frederick, John, William Henry and Alfred.
John Peter Stroh married Catherine Muller in Liverpool. I haven't found a date for it but from the birth dates of their children I would guess it would be somewhere in the mid 1880s.
Incidentally, I believe that the family came from the Kaiserslautern area of the Rheinland-Pfalz not Bavaria.