How much would it cost to have a ultra sound scan on my ankle?

I chipped a bone in my ankle 8 weeks ago but i still have a lot of swelling im going to physio and going to try the hydro pool twice a week but the physio thinks i should have had a scan befor now to see what was going on now they are saying i need to see my gp for a referral im just being pushed from pillow to post so was thinking of getting it done private