It does help, Darren, and I thank you for your input. At the time I bought the battery from China I also bought one from Radioswap and so far this one has been fine. It's too soon to say whether it will last a reasonable time (say 18 months of average use) so I will report back if I get any problems before then.
It's hard to know what to do because it seems the 'genuine' batteries are mostly fakes or seconds and the compatible batteries are a leap into the unknown. Neither are cheap.
If anyone else has any input then please share as there are a lot of these Hytera radios in use now so batteries will be a concern to many. Thanks.