Thanks.
You are right I will not need any higher frequencies for the lab setups, but it would be nice if they werte good enough to be useful also in other setups. In regards to using the "B" series picture I don't think so. The (limited) 3rd CH is actually on the back on the 3 CH versions.
So my guess is that Hantek tagged on a 3CH in a "Frankenstein" way on their existing 2CH generator and the only spare room was on the back. That is most likely also the reason for the limitations. They crammed as much they could from the existing architecture (CPU speed etc.) without having to make substantial upgrades.
I have only been able to find one place to buy from,eBay.de. It can also be found on Aliexpress but the seller have ridiculous freight prices to Europe, 60% of purchase price so that is out of the question. They also only carry the 20MHz version and not any of the higher spec models.
I will buy one to try out (and post results back here). I still have a lot of time before I have to get serious for the course!