Got to fly from Gatwick next week and rather than take the car to the
airport as usual I see I can get the ELL to New Cross Gate and change
and get there in about an hour. Question is on fares – National Rail is
showing a chapest fare of £19.60 from Dalston but if I got to say
Farringdon the fare is just £9.90. Is it possible/best to use Oyster to
New Cross Gate and buy a single from there?

E.