But there are no guarantees, so you need to be prepared.This used to be one of the main grounds on which you could dispute a ticket, but making that argument's become much more difficult since last November's Supreme Court judgment on 'excessive' charges.
You'll need to submit a statement, called a 'particulars of claim', which basically means a letter setting out the grounds for your seeking a refund.
If you're sure it isn't a member, jump to: How to dispute if the parking firm IS NOT part of a trade body.
There's also another route you can try, whether or not the parking firm belongs to a trade body.
In the past, some lawyers argued that a parking charge must reflect the loss to the landowner by you parking there, so could a company really justify a penalty of up to £100?
But Supreme Court judges ruled in the Barry Beavis case that £85 was not excessive for a 56-minute overstay, and that fines have a "useful" role to play as a deterrent.