Not as simple as that now.
Just been through a long and tedious battle with the HMRC on this and didn't win in the end. Others have done it in the past but I think they've picked up on this now. You may be able to claim back some CPL costs once you have trained AND are self employed but as far as I can see now you will not be able to claim the VAT back on training flights as you go along.
As a bit of a warning to others, I paid the school I was training at a sizeable amount of money to help me do what is mentioned above. They claim in their 'Career Seminars' that lots of people have done this before and is relatively straightforward. However, when it came to the crunch they took my money and weren't much help at all, when HMRC started asking questions.
When I asked for some of this 'consultation fee' back my emails and calls were ignored. This is not a small training company either. Unbelievable.