So it seems that since disconnecting the battery and then reconnecting it and doing a full charge - my issues have been fixed!
I've now been using it for 3 days and the battery indicator is still full. Previously I only averaged about 400 page turns. Sometimes it would go flat within an hour of charging.
So for those having battery issues that can't get warranty - I'd recommend discharging the unit completely, disconnect the battery for 5-10 minutes, reconnect it and then do a full charge.