Managed to strip the thread on a "wrench" (if thats what its called ?) while putting a tyre back on my wifes nissan ... (got a teary phone call a hour ago that she was stuck in the middle of sainsbury car park

) Anyway all sorted now apart from the wrench thing.
Is its a wrench that is used to tighen wheel nuts ?
Where can i pick up another ?
Are nuts all the same size ?
thanks for any advice.
Scott