Candidates intending to apply in 2014 for entry to a relevant course in a UKCAT University in 2015 (or for deferred entry in 2016) are required to sit the UKCAT by 15th October 2013 deadline
The UKCAT test you take for this year can only be used for medical school applications for entry in September 2015. Were you to have the misfortune of not obtaining a place, you will have to take the UKCAT again to accompany another application.
So, the UKCAT score does not stick. You will have to take the test again the following year.