Bob Eager wrote:

Not exactly. There is a provision for televisions used (inter alia) by
students living away from home, and (I believe) caravanners.

The "student" exemption was withdrawn a good while ago (20 years back?)

I'm pretty sure (from memory) that the batteries have to be 'internal'.

That, I think, is the case - "solely powered by internal batteries". It
would take dedication of a uk.d-i-y variety to make up a spaceframe
around the bulk of an existing TV set, with two or four deep-discharge
lead-acid batteries, layered in photovoltaic cells to keep 'em topped up ;-)