can't say exactly with these details. But I have a doubt about your data set.
your end date is end: "2014-03-26T11:02:34+01:00"
your start date is start: "2014-03-26T11:00:30+01:00"
if you can see the event duration is nearly 2mins.
Now take a look at the picture. your event time step gap is 5mins. So it can't show you the 2mis duration in a clear manner. But yet I can see some little deviation. (I think you are doing it correct , and you have got the correct result
).
I think here your problem is your event duration is too small so you can't see a big difference in the display. try event with a big duration. I think you did it correctly.