Okay, I know it has been a while since I updated this, but I have only recently bleed the clutch and been able to drive it.
So far from my minimal driving, there seems to be no issue with the firewall flexing etc. Obviously it may change when it is getting abused/kicked, but I will report on that later. For the moment though, with normal driving, it operates perfectly
My only change (personal preference) will be to replace the standard pedal return spring with a slightly stronger one. The stock one works fine, but I'd prefer if the pedal felt a bit more firm/harder to press.