a) Taking them out of one nursery aged 3 to put them in the preschool attached to the primary school they'll go to for a year before Reception. Will know loads of kids in Reception as more than half go to this preschool. However will have to resettle in a different setting at an age when this can be tricky.
b) Keeping them in the other nursery until they're 4 and then sending them to Reception in a setting that will be unfamiliar and where they will probably know a handful of other children (prob about 3 or 4.)
Interested in hearing people's thoughts and experiences as many many others must have been in this position before. I may be overthinking this!