SOLVED Children turn invisible by going round fairy ring [s]

[Ankur]

A new girl to a school shows her friends how to turn invisible by going around it in a particular way (maybe backwards). They call themselves the " invisibles" and do things, then go to the fairy ring to turn visible again; the girl has made groups like this in other towns before. Their clothes don't turn invisible so they have to take them off, but they can see each other if they are also invisible. I read it in ~2001.

[Bryan457]

Possibly .

Rosie knows that if she walks backwards around a fairy ring she can become invisible and after some persuasion she lets her closest friends in on the secret. Following a series of expensive art thefts from nearby houses, locals begin to suspect Rosie's family--travellers who will move on at the end of summer--and she decides join forces with her invisible friends to do a spot of undercover investigation of her own.

[Ankur]

Thank you, that's the one.

[Bryan457]

YVWC!
:-)