If I understand the vagaries, I think a few years down the road UK players won't even notice the tax as it is a tax on Amaya/PS/FT and other participating sites profits, not a players tax.
Of course their will be accommodations made by sites to increase revenue flow... affiliate and PRO disassociation is already happening and I would hazard a guess that rakeback/rewards programs will be reviewed and changed.
Smaller skins have chosen to leave the UK market, Merge/Carbon being one. Since that is a site USA players can play at (excepting a few states) we here are sad to lose our UK friends.
Hopefully this will all sort out to the good for all of us worldwide with regulated sites and we can all share a common felt in the future.... until then, best of luck.