50 pence collecting is very new, but I think it's a fashion which will last, so I would expect some of these other sets to get more attention, and it's great for the hobby - I think past waves of coin collecting have sprung out of people being able to find rarities in their change - think of US collecting in the immediate post-war period (when you could get things like 1932 D quarters in your change), or the British market in the 1960s around decimalization.
Whether it will make the 1970s sets worth £50 each is another matter. I hope not, but then on the other side the wholesale price being around £5 a set at auction is a little silly, especially given the difficulty of finding some of the sets with red lustrous copper - I went through a whole dealer's stock of them recently and found none I wanted to purchase. Probably the value for all of these will settle somewhere in between.