Provided the correct filler rod was used and there wasn't too much heat to distort the centers, filling them like that is totally fine.
Turned on a lathe and then rebored to 4x100 again is totally fine if done properly.
Kudos to getting it sorted out Mr Blue 
Thanks Neo

Do you do machining?
Yes done my fronts this same way and CBF to run adaptors on the backs any more.
Heat was kept down by switching from wheel to wheel. Hopefuly I don't find air holes when it gets milled back (quite a big fill job)
The 4x100 PCD holes are still going through the original wheel material. The 'filling' is just doing its job. I've seen 4x100 redrills without the gap filled and a piss poor job from such a respectable engineering firm on another forum
