I am not 100% sure if this is the same problem as you are seeing Andy, but I noticed last night before I plugged it in to charge, that my battery meter was still showing 100% even after a day of quite heavy use for me. A power cycle dropped the meter down to about 30-40% which is more what I would expect.

Never noticed this before, I have been keeping an eye out I suppose since I saw this post. Not a real big problem for me as I am in the habit of plugging it in every night whatever the charge level.

Cheers

Cris.