Now does not work over VPNs from anywhere to anywhere.
You might have more luck with Smart DNS, but I have found that to be a game of whack-a-mole.
You can download Now programmes while in the UK and then watch them abroad, though. OK for On Demand, but not much use for Live, alas 😢
I think NOW put more effort into spotting VPN's than most , however I have to say in my case I spend 3 months in UK and 3 months in S.E.Asia and invariably the £20 Sky Sports offer comes around when I'm abroad and I'm not able to take it up but on returning and a brief explanation of my plight they allow me the offer price even if it's expired. Due to the impossible streaming while I'm away I cancel my sub before I go to save wasting....