Thanks for your comments. Jenny – I was covering bases yes, but not necessarily in case of an underlying physiological reason, but I like your thinking and will definitely consider that possibility in future.
As a small update, the child still insists on going to the park and playing with dogs. And now wants a dog! Oh and they’re not called magic circles any more – apparently they’re now called rainbow circles and they’re stronger! He’s taught his 3 year old sister how to make them.
On Friday I am meeting a mother with a 7 year old daughter with a similar phobia, and had enquiries from a third. Referrals via a satisfied mum! If this ends up my niche I can only say I didn’t see this coming 😉