Day & night leaking / wetting

[Teddy500]

My son is 10, on 4 sachets of Movicol a day (to ensure he has at least one soft bowel movement a day) & 5ml of Solifenacin, lots of water. As far as I can tell he gets the urge to wee when his bladder gets to about 100ml, he then tries his best to suppress the urge, but a little bit tends to leak out when he does, this will happen a few times then he goes to the toilet when he feels he has to and it will be between 150ml & 200ml. He wears pull ups at night. Did a full and complete disimpaction over summer which made no difference to his bladder. Very slow / little progress with NHS (fair enough in the circumstances). I'm very concerned about him coping at Secondary school. Can anyone help, tips, ideas please?