Next step to modifying the control app was to look at the MIT AppInventor. This tool is described at http://appinventor.mit.edu/explore/ To install the software on my winxp computer I followed the steps from http://appinventor.mit.edu/explore/node/165.html
Having got it installed I decided to try the "HelloPurr" demo app at http://appinventor.mit.edu/explore/hellopurr.html which makes a cat noise when the Nexus 7 screen is tapped. All was well, following along with the directions until I tried sending the app to the tablet. Initially I tried using the apb method through the usb cable. The computer recognised the Tablet but I could never get the adbdevices command to show the device was other than offline. I tried the wifi method but this was doomed if you have no control of the hotel router (I couldnt ping the android from the pc).
Looking around the tool, I noticed a "Package for the phone" "download to this computer" option which generated an .apk file, which by now I had learnt was the install file on an android. I also remembered that when I installed Google_Nexus_7_ToolKit v5.1.2 (needed to unlock the tablet so i could install non Google approved apps) It had an option to install an application from an .apk file through the USB cable. So I tried this method and the app installed.
For interesting reading material see the .pdfs at http://www.appinventor.org/projects
Next task is to see if I can modify the control app!