On 17 Jan, 17:17, JB wrote:

So would a Cambridge to R456 season ticket and a TfL zones 1 to 3
annual travelcard be valid for a non stop Cambridge to Kings Cross,
since it would appear both are zonal tickets?

Interesting qn; anyone got a convincing answer? I'm fairly sure the
answer is that it would not be valid, but I can't work out on what
grounds the C-R456 would be defined as "not zonal".

If so, if you had the TfL zones 1 to 3 on an Oyster card, woul this be
a problem, as you would need to use the Oyster to out and back into
Kings Cross?

There's no problem entering or leaving KX with a z123 season ticket on
Oyster (indeed, I've frequently gone from KX to Finsbury Park on NR on
a z12 season ticket on Oyster) - an Oyster season ticket is valid at,
and will open the gates at, any station of any kind[*]in the zones
for which it is valid.
[*] yes, pedants, even fire stations and police stations.

--
John Band
john at johnband dot org
www.johnband.org