I would be pretty surprised. Not everyone in the UK has ID, and since the NIC scheme failure, it's less likely than ever to happen. ID isn't even required to vote at the moment...
People likely won't resist it too much. We've had this identification requirement imposed upon us in the Netherlands a few years ago, and while there is valid criticism on this requirement, it passed. So to vote now you need to bring a valid ID. If the British government wants to do this with a minimum of fuss, they'll do what our government did and make the driver's licence a valid identity card. That way the majority of adults will already have their ID on them as a matter of habit (and won't complain).
Of course mentioning that it is needed to prevent Muslim voters from committing voting fraud (see¹…) will help push the bill trough.
1: http://www.telegraph.co.uk/news/2016/12/27/voters-will-have-...
Only an extraordinarily confident and popular government would have another go (and it's not what the UK has now).
As for the voting scheme you describe, it's entirely voluntary, for 2018, and no council has signed up yet.
Things may move in that direction slowly, but to suggest that the UK is particularly close to requiring ID for internet accounts is downright silly I'm afraid.
Of course, most people tell their friends which way they voted, but that's their choice.