I've not got a jack
if that is the problem is it an expense fix?
Well I was going to go back to the tyre place today and ask them to have another go.. I thought maybe its just the alignment is out when the steering wheel is lined up straight? I could ask them to have a look If they think the ball joint you mention is worn when they jack the car up to do the alignment check
like I said my steering wheel has been off centre since as far as I remember, prob from when I bought the car last year