You should be able to do this with the Ondemand plugin which you can download from the plugins menu with the 4D image. I've struggled with compatibility with this (was working, then not) - but have loaded lots of different images periodically on the box, so may have messed up the software somewhere else.
On the plugins menu it is Ondemand 1.6 version, but seems there are later versions available, seen 2.0 elsewhere.
Have another receiver (GI Genius / ODin M7) running same chipset as the TM Single & spec running the OpenAAF / Open ATV image which has the full Ondemand BBC, ITV, 4OD and RTE players all of which work overseas without VPN (i'm in Spain).