I faced the same problem. Their website cheerily advises you(used to file down the axel) cheerily advise you to file down the axle...
I did it anyway, just using a hand file. Not the tidiest of jobs but got it on the forks. So far works really well. I'll try to remember to update this post if it ever goes wrong! (If you're reading this in 2022, feel free to nudge me for an update).
The problem with that though is then if you want to transfer the wheel to a new bike, you run the risk that it's then too narrow...