So, update: I have temporarily hooked the computer up to a 16mbit connection and time to menu was under 10 minutes. Roughly 7 times faster, using a connection that is about 8 times faster.
I have nothing at all in my community folder, but definitely making progress on the debug. Over the weekend I’ll have a go climbing up a post to get line of sight for the temporary connection, speed may increase further for a third data point!