UPDATE:

It is simple seo url that is stopping it from working, when I have SSU disabled, https works with using "server ip/username" (with username either after slash or in define('DIR_WS_HTTPS_CATALOG', '/~username/'); a bit further down (like it says to do it in install notes for SSU).

BUT

When I enable SSU, I get the 404 error that I quoted earlier, does anyone think that this is because it is an ip address as opposed to a url? (like I said, it does NOT work with using the url and it was my host that told me to use the ip for my shared ssl details)

Bit stuck here, anyone?