"a TV to watch videos costing the modern equivalent of £50."
By 1981 home video recorders were becoming commonplace. My JVC VHS "portable" with a colour camera cost £1300. Bush, Baird, and Ferguson sold re-badged home recorders for a few hundred pounds. Comparable to the colour TVs which graced most homes.
Probably every high street had an independent video rental shop. The tapes you could buy at £50 a throw were mainstream big films. I still have "M*A*S*H" which was £49.99 - the only one I ever bought. There was a booming trade in rented videos - and soft pr0n was a novelty expanding the market for newer creations like "Debbie Does Dallas" and "Flesh Gordon". Hard pr0n was probably only available under the counter as it was still liable to prosecution under the Obscene Publications Act if flaunted too openly. Three hour compilation tapes were quite common.