Pair of Wellies, £1.50 in Home Bargains. There is NO excuse for your DC's not being properly equipped for school.
I do have to say, though, to the naysayers, that my DC's Primary school will not help any DC's with 'self care' skills like zipping up coats, putting on gloves, putting on wellies or snow boots, or changing for PE, unless the have a full statement of SEN for a physical disability.
Which is a PITA if you have a DC with a physical disability that is on SA+. I used to have to go in twice a week to get DS2 changed for PE and back into his uniform, right up until he was halfway through Y2.
So no, not all schools will help. I DO believe the OP on that one, having had experience of a school like that myself.
However, my DS2 has a physical disability that DOES make any fine or gross motor control skills like dressing take longer to acquire, and I have had to find 'cheats' for PE days to enable him to change without my help. He still cannot do up buttons and he is 9yo.