From reading more on the e83, it seems like the white cable is the BT antenna, not purple like on some other cars, so we should be good to go.

Gf just went halvsies on a computer from eBay with TIS, GT1, NCS expert, Progman etc on it, cable etc all ready to go, so sometime next week I will be trying to give this a go.
I hate Windows machines and didn't want to deal with the headaches of trying to learn unfamiliar software, plus set up of half a dozen programs and the computer itself, so this option worked out great for us even if it was more expensive than buying an old laptops and setting it all up from scratch.