I took mine last year and I managed to do it 4 hours before the finishing time by just getting the horrible bits out the way first. If it's still the same test to the one I took, You will need to fill in all your materials and tools sheet and I remember being told that they won't accept anything under 45 materials, the tools sheet is basically a tick sheet of the tools you might need. When I did mine they were very strict on measurements and secure fixings.. to the point they would try with all their might to rip it off the wall, which is why I got a credit and not a destinction.. any who.. like I said if you've done all your NVQ work to the book and you think you're competent in that you'll have no problems, try and not let it get to you and try not to worry about time and whatever you do don't cut corners, I know 3 people who failed because they tried to do a job to quick.. ended up costing them another 12 hours to re-do the test!
all the best for it.
