As an aside, Leighton Buzzard is one of the 53 stations in the extended Pay As You Go area that’s due to be introduced by the end of the year, so you’ll be able to use contactless (but not Oyster) all the way from Leighton Buzzard to Kensal Green when it goes live.
Source: https://www.gov.uk/government/news/53-train-stations-to-benefit-from-tap-in-tap-out-rollout (DfT News Story from July)
