Blimey, took me nearly an hour to catch up on the end of the last thread and this one.
For the record, I'm also 53 - we used to always have R4 on, though mother used to complain about TA: 'I don't know why we have those people on, always arguing and complicating their lives' - her euphemism for extra-marital goings-on.
IIRC I got properly hooked on TA when I was a postgrad - prior to that my fondness for R4 started with the comedies and JAM but it was Hitchhikers which really made me an addict. its been a bit downhill from then on though
This shit thing about 'bringing in older actors to play younger characters' - hope S O'C hasn't forgotten that this can lead to the actor getting past it (or expiring) before the character is due to SOTMC - he needs to think in terms of decades, we don't like recasting (though New Tony is fine but you won't always get someone of that calibre).