Hello, I hope the following is of assistance.
As the car is a 2011 car it should still be under the 3 year 60000 mile warranty, there are a few concerns on the Ka that can cause starting problems but to accurately diagnose requires the car to be connected to Ford IDS, this should be done free of charge under warranty.
If there is a problem with the timing it is possible the timing belt has jumped a tooth, there were problems with this on cars built around 2010, this normally leaves a fault code P0016 that would be retrieved by Ford IDS.
With regard to an ECU problem if there is a concern with this it is usually a software error rather than a hardware fault so it would be a case of the PCM software been updated with IDS again this should be covered by warranty.
If you normally get your fuel from the same place it may be worth trying a different brand of fuel, the Ka is a little notorious for having running concerns with lower quality fuels, below is a message from Ford issued to dealers regarding this.
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There are other concerns that could cause poor starting, the ignition coil assembly does cause problems, also make sure the spark plugs are OK as these need replacing every 2 years on this model. Check that the breather hose from the valve cover hasn't split as this is another common concern.
Start with these points, let me know if I can assist further or if you have more questions regarding this and I'll reply as soon as I'm able to.
Best wishes and happy new year,