Hi gazumped and thanks for your reply
I am measuring the memory use from within the settings menu on android (6.0.1). It splits it out into app and data, with my numbers being 53,26 MB and 2.00 GB, respectively.
I have all of my notebooks set to offline as I often need to access reference material on the road where mobile data is not reliable enough or too expensive when abroad!
Since posting I noticed that podcast addict was using over 1 GB of space in internal memory as well. Luckily resolving this was as simple as going into the app settings and selecting save to SD card (it came up with a warning about apps only being able to save to their designated folder but selected this automatically)
This workaround would probably work but I dont really want to delete evernote every time I want to install a new app, and then have to sync my notebooks again (on mobile data if ont he road!). This is more an issue with updates though, as I get error messages as android attempts to update installed apps. It will complain about a lack of space and ask I delete some files. Unfortunately most of the data is apps but most are < 50 MB so don't offer much extra space
There may be a feature in android that will help with the issue. I have just seen an option on the same screen that displayed the storage usage for evernote and it gives me the option to move to SD card. I have chosen to move to the SD card but so far it is not reporting lower internal memory usage. I will probably check on this tomorrow to see if its made any progress.
However, having just gone through the rather straightforward process of setting podcast addict to save to the SD card, confirming that it works correctly as well as finding the folder it saves to (fun fact, there is even a folder on the SD card for evernote...I wonder why the app doesn't use it??), I really think this should be a standard feature.