Colin Rosenstiel wrote:
And why does a ticket (e.g. a Saver Return) to Putney (SWT) cost so much
more than one to Underground Zones 1 and 2?

That annoys me too! I think to Putney we pay three bits:
1. - London
2. Cross London tube transfer
3. London - Putney

Wheras to East Putney we pay two bits:
1. - London
2. Cross London tube transfer

It's an irritating pricing structure because there are many journeys
from the Putney area to Central London which are much quicker and much
less congested as Train + Tube rather than Tube + Tube + Tube. But the
quicker and less congested one costs about twice as much

Chris