you dont need PR, DSS lives with me and DH and has done since he was 14, I have always taken him to doctors, dealt with school, etc, when DH was working away, DH simply took me to school and introduced me, put me on their contact forms.
It was never formalised, we just did it that way.
You are wasting your time totally going to court to establish residency for a 14 year old who wants to live with you, and any solicitor who tells you different is simply after your money.
I KNOW WITHOUT A DOUBT you mean well, but the courts work on a no order principle, by the time this gets to court, DSS will be 15 (if you are lucky and it happens quickly) and I very much doubt any judge will see the point in issuing an order for a child that age, who can simply walk with his feet, unless there is fear of abduction.
The ex cannot issue instructions to the school that counter act the requests of the RP, and in fact neither can the NRP, its to stop the school getting drawn into conflicts and is new government guidance, so for example DHs ex cannot say that I cannot pick DSD up from school, to the school, unless there is an order with that specific clause.
If they did (espeically a 14 year old) they are inbreach of government guidance and you need to take that up with the school, I used to have a copy of the relevant guidance, provided to me by our solicitor