This is a link to the video I did for 2nd hand cages, listing external measurements.
Look out for these and any of the ones shown in the previous post on 2nd hand websites such as gumtree, shpock, preloved and facebook marketplace.
10 Good 2nd hand hamster Cages | Cosmic Hamsters #shorts #hamstercages - YouTube
I think with both videos that is a total of 26 different types of cages to look for. I will be doing a part 3 for more bin/diy and ikea cages... will post the link once I do it.