Thanks for the updated info. There has been some continuity introduced
in the prices, for example the z1-6 discounted cap on Oyster PAYG used
to be £4.60, whereas the cash price of the discounted z1-6 paper
ticket OD Travelcard was £5.00. Both fares are now the same. £3.35 for
z2-6 cap ( including all the NR Lines within the zones) is a damn good
value in anyone's book !