Not that I'm aware. They're 39.99 each. Not cheap, but a long way from the £60 I was looking at paying for getting some from Germany or Italy last month.
Given the way things are going - it might be prudent to stock up on expensive Italian tyres now, before they all cost £80 a pop.
I just bought a bunch off PX too.. decided that nothing is worth using Challenge, even £10 off per tyre.