Thanks for that, CaroleW.
It's a bit more complicated than that - I know who and where but I wanted to know how. My mum (still alive) was moved from London to Hitchen, then taken back to London, moved to Wales then back to London, to Dorset then back to London and finally to St Albans where she stayed until 1947.
I'd like to know how these placements were organised - if initially they were arranged by local councils/education departments (as most kids moved en bloc with their schools) but later arranged privately. Mum was too young to know and there's no one left to ask. I might not be able to find out anything at all but it is interesting that the county archives that do have evacuee records (more organisational than detailed individuals) do not say 'closed for 100 years'. I've not tried to see them yet but wondered if anyone else had tried.