Got the firelight forks fitted and everything hooked up .
No real issues in the end ;got steerer cut ok and even managed to re-connect the hose without needing to bleed them and the hose was (just!) long enough to reach. Had to find some different stays for the front mudguard and looks like there will be loads of clearance for a 35c at the front now.
Was going to swap the GRX rear brake for an Ultegra one but ran out of time.
Will give it a gentle spin tomorrow to test it's all ok and then double check torques and thread lock mudguard and front light bolts.