The sign is interesting, thanks Mhale, as it shows she left London a lot earlier than when the Mappins were emptied (although I'm not 100% sure about the records Ben Mee would have inherited from the previous owner).
It is interesting that, although the Dartmoor sign states this bear was born at London Zoo on 15 January 1978, the ZSL Annual Report for this period records that the two brown bears born in 1978 both died within 30 days of birth.
