Your setup looks almost identical to what I ran at the Clubmans (apart from a lot less rear toe since you're in 17.5). I don't think there's a lot left to try...
Some toe-out on the front will help it to turn in.
Going to the mid position on the front camber links (i.e. longer front link) will give more mid-corner steering, at the cost of a bit of stability on the power, which you can probably live with in 17.5.
Likewise for split front blocks or a solid rear block.
I see you've got kick-up on the front, which isn't something I've ever tried. Did this increase steering? Generally any angle on the pins should reduce grip through the corner. Plus the increase in castor angle will have reduced turn-in. So maybe try going back to horizontal.
And let me know how you get on and what works, it will help me out next year
