Any time within that window, the CPL and IR can be done in 3 months, start to finish, and at a time that suits you
Nice in theory, but it can be very different in practice. Whetever prompts you to do the final bits (probably Airline XYZ starting to recruit) will cause (a) every other person in the same situation to want to do the same training and (b) a significant proportion of the instructional staff will be in the first wave of departures to go and work for XYZ.
Put those two things together and you have a witches brew for delayed training. The cumulative effect has to be seen to be believed - I'm not just talking about a few weeks! I've seen people needing to wait for a year to get a course, and another year for a test slot. (although to be fair I think the latter situation is much less serious since GFT examining authority is delegated by the CAA).
How do you know an FTO is BSing about aircraft/instructor/test slot availability? Their lips are moving. (an old recycled joke I know, but apt in my experience.)
pb