Basically, u could choose which book u want ur test to be based on. The old test will still be valid till the end of June.

However, just be aware that there is a lot of confusion going on even among the test center staffs. I was told by one centre that I have to study the new book and wait till April to take the test. The other centre has no problem with me wanting to take the old test.

I phoned today for an appointment I live in the west midlands and birmingham is the closest test centre for me.  the earliest appointment I could get after  phoning 5 test centres is 4 April and they confirmed that until 30 June you can still do the old test.

Hope they are right!