I’m still confused! In some places I see it can’t be used on Greater Anglia at all, in other places that it can be as long as the train stops at Romford first. I know it can be used on the Elizabeth line.
My journey is from Stratford to Shenfield and I have an Oyster 60+ card. Travelling about 11am.
On paper it’s valid on GA as far out as Harold Wood, but GA trains don’t stop there. But that doesn’t mean you can’t buy a ticket that’s valid from there. Ticket buying site https://Tickets.railforums.co.uk allows you to tell it you have a Freedom pass, 60+ card etc and works out the fare taking it into account.
You may be surprised to know that some staff at Greater Anglia are confused as well. In terms of a Stratford to Shenfield journey you’re probably better off using the Elizabeth line as it’s then free all the way. If you want to use the fast trains then you need a boundary zone 6 to Shenfield ticket which can be bought online as Colin suggested in the post above. The 60+ Oyster is a zonal ticket, so there is no need for the train to stop at the last station where you switch to the boundary ticket.