So I've got another of the BD batch of batteries, and I've got the same problems:
- Battery jumps from high charge (eg 80%) to very low (around 5%) on random occasions
- Phone will turn off (even with a good amount of battery left) and fail to boot (boot loop) unless I plug in a charger
- Battery is slightly swollen (not as bad as some that I've seen though!)
- Generally bad battery life
It seems as if it's only batteries with the serial numbers beginning with "BD" that are affected, and it may not be all of the batch, but it seems like it's quite a common problem for this batch.
Luckily for me I've contacted the shop I bought it from (Amazon UK) and they're sending out a new handset which should arrive in two days. Can't fault their service!
(Posting this in both threads as it may be of use to people - Maybe the mods can merge the threads as they're both pretty much the same?)