Here's a Thursday morning thought Clipclop: why not use your contacts to make your initial set-up in partnership with an existing school.
You could look at any combination of staff children and local working parents but it is something that a school could then declare on their Ofsted self review framework as 'working in partnership' and 'working with local communities'.
In particular primary schools with falling infant rolls might welcome someone renting an area which would come complee with tiny toilets etc...