Section B first or Section A?

depends on the paper… start where you feel most confident, and stick to your timings.

my personal approach to P papers is:

15 mins reading time:
scan all 3 B questions, choose two.

Use the rest of reading time PLUS 15 minutes to plan answers to entire section A question
(2:45 to go)
whether plan is finished or not, start writing for section A – 1.5 minutes per mark, 1:15 total

(1:30 to go)
for each B question:
7.5 minutes planning entire question, going over scenario and making notes.
37.5 minutes writing @1.5m per mark.

I find this approach helps ensure the entire question gets answered and you don’t put the wrong bit in the wrong part, (like mentioned in q1c what should be in q1d)