i spoke to a DFR guy today and i asked him if the gap yr is popular and he said that just over 1000 people are competing for the places available, he gave me some advice that applies to everyone here, dress your best, present yourself to the best of your ability, and try your hardest in the testing.
The people testing with me today, some of them wern't the sharpest tool in the shed, so if your smart enough (and by that i mean know what 1+1 is ) and arrive on time (some people arived 30 mins late), neatly presented (not as tho your just off the street) you should do fine.
Just practice doing the tests they give you, and google some just to be sure, but know what cosine and sin and tan are, but at the end of the day its hard to study for so u either got it or u dont, if u dont, its nothing to be afraid of, just means your specality lies somewhere else.
good luck