It's the age of the child that makes the difference if they're not at full time school they use an early years place and if you need cover in holidays too many will charge, some don't you may be lucky.
It is not an unusual request at all, but you would probably need to narrow it down beyond NN3 and specify the school, as a CM may only be able to do pick ups from a school that they already go to as can't be in two places at once IYSWIM.
Dh just got offered a job (yay!!! - he's been a sahd but we need the money) but that means we need a childminder that is able to pick/drop off at school preschool. Is this a usual request of childminders, would they mind doing it? (School/preschool on the same site) and also f/t care for our 17mo old. Anyone know anyone in the nn3 area with vacancies???? Thanks x