Hi LPOak
I'm afraid I've no idea what a PPL1 is!
This is the way it works (to the best of my understanding -or did work 2 years ago when we first applied for our son to get into reception).
You put down your preferences for 6 schools. The order does not matter in the sense that if you put your closest school down as 6th choice, and someone else further away puts that school as 1st choice, your child would still get into that school if they had not been allocated a place at any of your top 5. Therefore you should always put your favourite schools first, but also should try and put one somewhere you think is close that is ok you could get into based on distance, for the reasons below.
If you do not get allocated any of your top 6 choices, you are allocated a place I believe anywhere there is space in the borough (I'm not 100% sure of that but you have to be allocated somewhere, so it depends on where there is space in other schools).
Typically people in this situation put their children on the waiting list for other schools. Pupils do leave schools, and some never start so getting on the waiting list can work. I know at least 3 children have left Dalmain over reception year.
We have been in the catchment area for Dalmain for the last 10 years, but the catchment areas have fluctuated. Stillness we have been in for some of those and not others (we were not last year).
I know one year 1/2 the intake was siblings which makes a huge difference to catchment area.
I hope that makes sense!