Hi Mike,
Many thanks for your reply.
It is quite unfortunate that the extension fares are not publicly avaiable. As you said, £2.20 for an off peak zone 6 to Maidenhead extension seems quite low. Also it is much cheaper than the off peak fare of West Drayton to Maidenhead, which is £3.50.
This raises the question that if I did split at West Drayton for the off peak leg, would I be charged more for it, or would it be the same? Also if I didn’t split at West Drayton in the morning peak time, would they charge me for a zone 6 to Maindeanhead extension automatically, which sadly we do not know the price of.
I understand that very likely we do not have sufficient informatino to answer these currently. I will be coming back in the new year to this site as you said to check whether any new information would become avaiable.
Thank you.
Robert