The only requirement for starting your CPL modular is to have completed the 150 hours TT.
The requirement for 100 hours P1 is not for the date of test, but for when the application for a CPL is recieved at Gatwick. The same applies to the Night Qualification training completed, 300 nm XC, 10 hours instruments, etc all need to have been completed by the date of application.
I can't confirm this, but I believe an application for a licence must be recieved at Gatwick within 6 months of a successful skills test, otherwise the test has to be repeated. Like I say, not too sure about this one though.