All very good suggestions and one worth considering :).
I will have a look online to see what Velcro shoes I can get and if not then I will get the school to help with the laces or just tie them in a double knot and let him put them on and off without untying them.
In terms of jackets, I always get a one layered waterproof warm jacket, usually from Go outdoors as, like you say, I'm not keen on anymore than one layer, tbh he will be warm enough with one layer when it's fastened up plus it is easier for him to move about freely if it's just the one layer and tbh these jackets are good quality and probably last a while.
I will also take on board what you say about jumpers and trousers etc so a huge thank you once again :D.