Alan - below are the instructions from my local library on how to download directly to an Android device using Aldiko, it works for me!
In order to successfully download to your Android device you must have the Aldiko app installed. Once installed and configured with your Adobe ID you can start to download your titles by browsing this site from your device.
Add us to Aldiko's "My Catalogs"
You can add us as a short cut within Aldiko. Doing this will allow Aldiko to automatically handle all downloads from this site. To add us to your Aldiko App, open Aldiko and follow the guidelines below.
From the main screen choose "Store", then tap the menu button (top right of screen) and choose "My Catalogs". To add a new catalog tap the "+" button. Enter a title i.e. Library eBooks along with our address
http://westlothian.libraryebooks.co.uk in the URL field. (N.B : The http:// is required to precede the our address). Our eBook service is now available in "My catalogs".
As I say this works for me and I'm hoping your local library service uses the same system. Good Luck!