I have not had a polar fleece coat - only the over trouser things and other bits which were all fab.love jojomaman. I think the jackets are double layer so warmer. personally would go for a waterproof as well as warm:
My son is tall and in age 3/4. I have got him a ski coat from dear2b as its ment to be a bad winter this year and we walk to nursary and school. I have also got him salopettes, all from go outdoors and a softsheel regatte coat.