I've just bought a roku and cannot access BBC itv ch4 ch5 channels.
I asked roku on Facebook messenger if I could access those channels once I'd connected roku to my WiFi and reply was YES!
Free view isn't in my menu either?
The channels available are dependent on your location, so specifying where you are might be helpful.
I'm in Luton and the roku is an express version
Not being in the UK, I'm not really qualified to answer, but until someone better comes along, I think you are referring to this:
https://support.roku.com/en-gb/article/360038618573
However, this only works with Roku TVs connected to an aerial.