I currently have an annual travelcard for Zones 2,3,4,5 and travel
between Harrow on the Hill and Highbury & Islington, using the North
London Line from West Hampstead or Finchley and Frognal. I understand
the idea that the Oyster will be "clever" and deduct credit if I go
into Zone 1 but if I beep my new Oyster in at Highbury, there is no
NLL to beep in out of, beep it in at West Hampstead Jubilee and out
at Harrow Met, how will it know I have used the North London Line?
Will it assume I have gone via Kings Cross and charge me an extension
ticket. Alternatively, if I am going via central London (if I miss a
NLL or it's late) and I go via Kings Cross will I get charged twice as
I go through 2 sets of barriers - Higbury to Kings Cross and Kings
Cross to Harrow?