Thank you all so much for your advice and comments.
Jenny is my friends 2nd puppy farm rescue dog but her first one didn't display the same circling problem.
I too adopted an ex breeding puppy farm girl 3 years ago, and although she has other problems, she doesn't circle, apart from just before toileting.
I will pass on all your advice, and if the vet check goes ok, we will have to assume that it's a result of being confined for so long, and hope that Jenny will eventually grow out of it.
Thank you all again..xx