Just to clarify, the above device is the Mullard Master Test Board which is Mullard's version of the Philips "Cartomatic". It had a rather short production run due to the war and is quite unlike the MHSVT so it's cards do not relate to the E7600.
But it isn't the oldest of these testers. The Philips P.S.T.T predates it slightly, but the MTB is rather more useful, being a lot more than just a valve tester.
Anyone interested in it can find a manual for it on my web site.
http://home.btconnect.com/gmb/