I assume your Raleigh has English BB threads, but you may not need to change the BB if you stay with a double crankset. If you find a double crankset with 110mm BCD, you can use an inside chainring as small as 34T. The combination that's popular right now in "compact" road setups is 50/34. I'm running 48/36 on one of my commuter bikes right now, and it's made a big difference from the 52/40 that it replaced. Lots of Sugino cranks have 110 BCD, and would look relatively "period-correct." Suntour "Signature" and Shimano "RSX" are other doubles that use the 110 pattern. I don't know European cranks in that size, but there may be some.

If that's not enough, you can go to a larger cogset, say something with a 34T bailout gear. To do that, you'll also need a longer-cage rear derailleur. In all likelihood, though, you'll need the longer RD just going to a 34 chainring, since you'd probably be exceeding the takeup limit of the current one.

All of this, of course, calls for some psyche adjustment, too. A classic with a long-cage RD doesn't look as cool as a short cage running over a pinecone, but there some aspects of aging that can't be avoided.