Well... actually, looking a little closer at what happened, i actually paid with my UK iTunes account,which went through fine.
More detail: I set up an Indonesian ITunes account, downloaded Vidio app (all on my iphone). I must have got distracted, but for some reason, I then logged out of the iTunes Indonesia account and logged into my UK iTunes account. I then turned on the VPN to Indonesia, opened Vidio app, created / logged into my Vidio account, it said "subscribe", i clicked 'yes', it then popped up my UK iTunes payment card / account and I clicked 'pay' (i.e. my normal UK iTunes payment - which is Revolut - it was £32.99) and it went through fine. The subscription is on my iTunes UK account - listed there. Maybe i was just lucky!