You can sideload them onto the two devices already running Android 4.2, to do this follow the steps below...
First you need to allow "Unknown sources", to do this...
Settings> Security> tick Unknown sources.
Now click on each of the links below to download the apk from my Dropbox (easiest to do this direct on each of the N7's that you want to install the app on), once the download is complete you will have a notification for each download so pull the notifications down and click a notification, you will be asked if you want to install the application so confirm and install one at a time.
Hope that helps, if you need anymore help, just ask.BBC iPlayer BBC Mediaplayer
These are directly copied from my Nexus 7's /system/data/app
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