There is an App available on XDA forums called Directory Bind, which according to the Developer allows you to move 'data' for apps to external storage.
Unfortunately, neither 4 versions of the app will actually install on my Tab 2 10.1, complaining that there us a lack of space, this could be down to me running CM 10 4.1.1, 'or' it could be a case that it only works for other mobile devices, such as the Galaxy S3.
I have posted a query to the dev, and i have my fingers crossed that there may be some light at the end of the tunnel.
Some of the replies from people using the app have reported being able to move huge chunks of data to external storage which is superb.
Here is the XDA link.
http://forum.xda-developers.com/showthread.php?t=1410262
http://forum.xda-developers.com/showthread.php?t=1410262If anyone has any luck can they post back.