Firstly, you need to login to the subscription site (if you have an active map subscription, otherwise you will need to purchase a subscription first).
Do NOT try and login to the subscription site if you do not have an account or an active subscription; if you do try to do so without an active account, you will be blocked!
From the Subscriber Home page, you will see a "My Maps" link on the page; to all the maps that you are subscribed to, click on the "My Maps" link, this will show you the GPS and BaseCamp for Windows and Mac maps too.
In all cases it will show you all the maps that you are subscribed to; such as for the British Isles, you will only see the British Isles maps, if you are subscribed to multiple maps, such as France, Spain, Italy and the British Isles, it will show you all of those maps.