NLTV appears to be viewable worldwide so there should be no geolocation restrictions on the IP address that your phone picks up (so basically it should work on your phone as long as you have a good data signal or a wifi connection)
If you’re using mobile data then what IP address you pick up will depend on how your UK carrier has your data setup, some use local breakout so you will pick up an overseas IP, some use proxies back in the UK to pick up a UK IP address. Either way though you should be fine to use your phone without the need to buy a local one.
