Fish,
I like the idea of theory online and the RYA seems to have done it very well. I'm doing a RYA online nav theory with practical exercises at the moment as it's been a long time since I did a proper course on the subject, and its really good. Example: I had forgotten all about the IALA zone B for lateral markers (in the US, Phillipines etc they're red to starboard entering harbor)
Good theory, well explained and if you screw up the prac or a questions, you get to retry. But you can only fail x number of questions.
I went through the Brisbane RYA school, they brought up the online training, explained it all and registered me and gave me the practical kit with all the web details.
The website portal fyr is www.ryainteractive.org, (but nothing to see, its just a login)
I would recommend it definitely. The practical is still practical of course, but RYA theory online I find excellent. Can't speak for Navathome as I haven't used it sorry.
Cheers,
SB
Edit: I still rate human to human training over online, it's just the convenience. The SSSC course is a great example, the benefit is being in the room more than the theory.