[G6Tanuki]

Like I said, I never came across tellies with such converters attached, or retro-fitted multi-channel tuners.

I suspect that in the late-40s/early-50s a lot of not-so-well-off people had held back from buying/renting a TV, but the coming of ITV was the 'trigger point' to get them to enter the market.

I remember quite a few relatives who lived in the 'margins' between Granada and ATV or ATV and Anglia, and who had something like a 5- or 6-ele Yagi pointed at their 'local' ITV transmitter, and a bayed 5x5 or 7x7 on top of the mast to get the more-distant ITV station. BBC Band-I was provided by a simple dipole on the 5-ele - meaning somewhat-indifferent reception.

"Oh, the BBC - we don't really watch them much".

As to converters, even in the early-1970s Fenwicks radio-stores in Wolverhampton had on display in their front-window 'island' a kit of coils to build a BIII-to-BI converter.... I guess they missed that particular boat's sailing by a couple of decades.