So this didn't work. Using the GUI (like you would in Windows, as I couldn't find a command line I was comfortable with), I moved all the files, sub-directories, etc. from the freshly downloaded magi-1453 folder into the original Magi folder.
I then tried to start the service but it wouldn't work. I renamed the existing .Magi folder - the one that contains the block chain, wallet.dat etc. and ran the service again - a new .Magi folder was created!
However it was unable to come online as there was no user information. So I made a new magi.conf file and restated the service and it seems to be active. HOWEVER, each time I do a 'magid getinfo' I get a reply that it's unable to connect to the server. I'll give it a little while to catchup with the block chain from yesterday, however I'm worried there's still more to do.
odroid@odroid:~$ magid getinfo
error: couldn't connect to server
Hope you get it up & running; it takes time to load up the chain, then you'll be able to check status.