I've just spent a week or two watching all the videos after finding the EEVblog. With the review on the Gossen Metrawatt XTRA, and Dave's enjoyment of the switch, I remembered that I have a 25 year old DMM branded BBC Goerz Metrawatt, model M2012. I've been searching for information about it on and off for years (decades?). I contacted Gossen in Germany and they were able to send me a manual for the meter (in German as they didn't have any English) in less than 36 hours! I'm impressed. I plan on translating this in to English and sending them a copy so they might be able to help out anyone else that needs it.
Btw, Dave is right... The Metrawatt selector is pornographic, even from the mid-80s!