Hi guys,
I normally buy an annual rail card from Forest Hill to London Terminals, but next April I'm planning to move to Zone 2.

I'm trying to figure out what the cheapest option is.

I was thinking to buy an annual travelcard for Zones 1-2 and from January to April to use my Oyster PAYG to fill the gap from Forest Hill to Zone 2.

Does anybody do that?
Do you know how much is it for the extension to Zone 3 for a journey at peak hours?

Thank you!

P.S. I've asked the train station and they didn't know...
I've also email TFL, but from previous experiences I don't think they will answer my email before April...