Today has not been wasted!
I learnt that it is in fact best or most efficient to install your solar hot water system's collector panels facing north.
I knew this was necessary for photovoltaic systems (or solar electricity systems), but thought that because there isn't the requirement to transform sunlight into electricity but rather just heat the water it isn't necessary for solar hot water. But it is! According to the information I have read if the panels don't face north, the efficiencies drop off in solar water heating just as much as in the solar electric systems.
So moral of the story, if you are thinking about either of these systems, orient all your panels as close to true north as possible.
If you have any experiences or comments on solar hot water systems feel free to post your comments below.