MIG wrote:

Thanks both, but it just gives me errors unfortunately, or tells me it
can't price anything I try. I does look as if it's offering
something, but it won't do it.

Try the Chiltern-branded version: http://snurl.com/3g26h

For the Destination, enter "London" and it'll give you both the
point-to-point and Travelcard rates.

HTH,

Barry