Look at CAP 804.
The requirement is 25 hours of time after gaining your PPL, including the IMC training, so if you do it in minimum hours 10 will be enough to start the training.
You also need 10 hours PIC and 5 hours cross-country PIC, but you normally have that from your PPL training.
As long as you don't bank on doing it in minimum hours, go for it!
[edit - that is the same MEL says, 10 + the course of 15 --> 25 before you can do the test. Technically you can start the training immediately and do the 10 extra hours afterwards, or if you take 25 hours to get ready for the test, that is it...]
Last edited by Cobalt; 10th Aug 2013 at 21:08.