I have been able to remove the main panel and I can see one battery however it looks like there is another smaller panel which I cannot remove ... any ideas?

jane, November 2014

this info is very helpfull ,I had to renew the batteries on a stannah 400,very fiddly getting covers off on left hand side of chair (facing chair)I just could not see how to get to 2nd battery,spent hours searching the internet for a solution until I found your post,different model,but same access to 2nd battery,the only things I can add,is the plastic front cover just clips into place,(no fixings) on loosening the 3 allen bolts,you will probably have to remove the right hand bolt,(I had to) then the chair swings over to the left and right,many thanks,Victor.

Victor, August 2015

if replacing main batteries and can not remove second one you need to[SWING CHAIR OVER] take the front covers of above footrest by two allen fixings situated behind/top,,then once remove the covers you should see allen bolts x 3 first mark with a pen/pencil where chair frame aligns with carriage covers so when you loosen allen bolts and then swing chair over you will then be able to remove top carriage cover to take out battery

From here: http://howtomendit.com/answers.php?id=444152

Anon, November 2014