Using uno telly i can watch USA netflix movies on my eg, tablet, but when I cast it to my TV a message pops up and says..( can't remember exactly).."can't access at the moment" or something like that, anyone else get this?

A bit more detail please !

What are you using to cast it to the TV? Chances are the device, eg a chromecast, will not be configured with the appropriate DNS settings (unless you've changed the DNS setting in your router). As a result, the device can't access content which isn't on the UK Netflix.

With Chromecast you can try the option of casting the tablet screen to the TV (rather than the in-app Netflix cast option). That works in casting the US Netflix, but I find the sound and picture is out of sync.

I can cast Progs but some films I can't.

Have you changed the router settings to allow the Chromecast to use other Netflix regions? Unotelly supply a tutorial on how to do this.

If you use a smart dns system, you set router dns to the smart dns addresses provided to you. You then have to use static ip routing (if your router supports this) to point addresses 8.8.8.8 and 8.8.4.4. to the ip address of the router (I also believe you can point to an unused ip address, and then router will default to router dns).

Search web or this forum for detailed guides.

If your router does not support static ip routing, it is cheap to buy a new one with staic ip routing and connect to main router. SEarch web fior guides on how to connect two routers.

I have not yet found a way to cast to chromecast when viewing by VPN (as oppposed to Smart DNS, but that does not mean it is not possible to do.