Just for future reference if anyone searches the internet for P20e action info (like I did)...
With little more than a truss rod tweak to straighten the neck, plus about 2.5mm filed off the (stupidly tall, IMO) bridge saddle, the action now sits happily at 2/64ths on the high E and 3/64ths on the low E at the 12th fret. This is very low for an acoustic guitar. I’m running EB Earthwood lights (11-52).
I also took the high E nut slot down a fraction, and I really mean a fraction! I was expecting to run into buzzing issues, but even with a capo on the 1st fret I get no buzz until you hit the unplayable frets beyond the 14th, and since I’ve set the neck flat I can always add in a little relief if it turns out I’ve set the action a little too low. I have a light touch so... so far so good.
Just to note, my guitar has a perfect neck angle and a pretty good fret job too. They just needed polishing really as they were quite scabby out of the box, but then so would I if I’d spent weeks travelling from China in a damp shipping container...
Oh, and I also smoothed out the fret ends, which were uncomfortably sharp in places.