As for childhood memories, it of course has to be Doctor Who, for all the obvious reasons. That, and assorted children's radio dramas with long forgotten names that made the interminable car journeys to my grandparent's more than a little bit magical.
In terms of legacy, I think the emergence of the Radiophonic Workshop is pretty crucial. When it started, sonic experimentalism was fairly mired in an open, and seemingly intractable, debate about the relative merits of musique concrète
vs elektronische Musik
You had, on the one hand, Pierre Schaeffer at the RTF in France extolling the virtues of working with found sounds; and on the other, you had Herbert Eimert (and later Stockhausen) at the WDR's Studio für Elektronische Musik in Germany declaring such practices retrograde and uninspired when confronted with the endless possibilities of synthesised sound.
It's to the Radiophonic Workshop's credit that they ditched such political and philosophical posturing in favour of a more open approach. Why not use both found and synthesised sounds? Why not take found sounds as your source material and then fuck with it? In short: why choose?
In real terms, the Radiophonic Workshop undoubtedly acclimatised the British people to the possibilities of sound, not just in a narrative sense (ie. its importance in the creation of atmosphere and mood), but also sound in and of itself (ie. what is sound? what is music? what, if anything, is the difference?). I would certainly regard it as significant that, when the means of production began to be opened up to the masses in the late 80s and early 90s, it was British musicians and bedroom producers that blazed the trail (in the same way that I know the Studio für Elektronische Musik to have been a strong influence on Kraftwerk in the 70s).
Obviously, that last sentence is purest conjecture, eh?
But I'd be intrigued to know to what degree the key players from the period would credit their own childhood experiences of BBC radio & TV programming as an early, and even ongoing, inspiration.
Would certainly love to read the fruits of your labours, monsterbobby; but I guess that seems a long way off right now...
Oh, and: nice thread