While that's possibly a way of doing it, I would still consider taking the pinch bolt out. I know it's a pain, but it could do with it anyway. If you ever have to replace a control arm you'll need it out. And once out the front suspension is easy.
We had to use excess heat on mine, they did exactly the same thing with the head just sheering off. It took 6 hours to remove the two pinch bolts.
I bought 4 bolts from the dealer: two replacements, one was for hitting to push the old one out, and the fourth was a spare. They're only a couple of quid each. Get in touch with stoke audi on here, they'll post them out to you if you don't have a dealer close by. I think four bolts, nuts and washers was about a tenner ish.
If you do remove them, cover them in copper slip so they don't seize again.
I think they're a one use part technically. As far as I remember the Haynes manual says to replace them each time you remove them, which seems excessive. But if you've already started sheering the head I'd really consider doing them. It seems like you've past the point of no return, but it'll be worth it in the end.