There’s two types of cancelling, one is wanting to change due to chairs not being comfy anymore etc, you’re allowed two of those (you pay £250 for this)
The other type of cancellation is if there’s something actually wrong with the car and it’s not fixable eg my 3008 screen stopped working (screen controls the heat/AC/nav, tried 5 times to fix it, was assigned a case manager from motability to deal with it, once it was deemed it’s not fixable they returned my full AP and no cancellation fee, I asked if this counts as a “cancellation” the case manager told me no as it’s not actually coming from me