In December 2020, I bought and Indivision AGA MK3 from GGS Data here in Sweden.
My first attempts to install it in one of my A1200s didn't work out very well (no picture at all in either HDMI or VGA modes), but that was probably due to the fact that the old Sony Bravia TV i was using.
I've now tried it in a different machine and with a different VGA monitor, and I get a picture, but it constantly jumps around between different display modes, and always need to press the mouse button to keep it from moving the viewable area around.
The A1200 in question seems to work fine, but hasn't been recapped. When I ran Amiga Test Kit, however, it shows timing/IRQ problems with the CIAA. Could this be the cause of the jumping display modes and the mouse button issue, since this, I believe is the CIA to which the MK3 is attached.