After a bit of a wait with my temperamental broadband, I managed to upload all the videos for each (Plymouth Route 1) marker. I have set the footage to play once the user is within 20m's of the marker. I chose this amount as with the current state of 3G in the UK, it can be a little unreliable at times, so this way the footage is likely to play when the users is fairly close, but not too far away. It also gives the user time to suss out the route ahead! The videos are also set to not be available until you are within range, meaning people can't cheat it essentially.
I then went out with my iPhone also to check a few of the markers to see if it would actually work as I had hoped and it did! You can see in the (screenshot above) me approaching marker 18, and once I was in range the video played as it should. It even loaded in a reasonable time with a weak 3G signal which I was happy about. Now I need to implement the footage on the Bovisand route, and finalise the short route around Plymouth. I will also be making the Layar elements more in tune with the look and feel of the brand.