Old MG's TV Now
 

Channel 81 Freeview...

Just missed it, will likely be on again (and again lol, it is Freeview after all), but perhaps it is HERE.

It was a GKN/Laycock old advert for overdrives, demonstrated using an MGB. I loved overdrives :D

that's the one. Still cannot get my head around an overdrive lol - how they physically operate without mechanical interruption.

another interesting video from that era HERE

Epicyclic gears and a clutch. Much better than an extra cruising gear on a gearbox for over taking. I could sit there in 3rd, overdrive engaged, see an opportunity coming up flip the over drive off, without dipping clutch or accelerator pedal and have immediate power to get past. On the way past, flip overdrive back on with no loss of acceleration. Once past, off again into 4th, then eventually 4th plus overdrive engaged.