I had my interview about three weeks ago and got an unconditional offer (I already have a degree so it's for the accelerated diploma).
The 15 minute essay was pretty easy. Basically they give you a short (one page-ish) article to read (it was about games consoles being used in science - for example the Nintendo Wii being used to help rehabiliate stroke patients) and you have to summarise the main points. Obviously it's only 15mins so you can't really write that much, but it's just to show that you can read and understand something I think. There was a maths test too, which was ok - the questions were mainly scenario based - like "if a patient needs 10mg of a medicine and the medicine comes in 5mg pills how many pills do they need" (maybe not quite that easy but you get the idea!)
It was a really good afternoon actually, so don't be nervous. After the tests the head of admissions talked to us about the course and answered loads of questions - it was very informal and extremely informative. Then we were called in groups of about 8 to go for a group discussion which was lead by two nurses/lecturers who were lovely. They just asked us to discuss what makes a good nurse and what we think we might find difficult on the course. They also answered any questions we had.
So anyway, it was really good and they let you know the outcome within about a week which is good.
Let me know if you want any more info x