I have to make a visit to FCC's central lost property office some time
soon. Will my Cambridge-London Terminals cheap day return be valid to
there (City Thameslink) via St Pancras International?

Alternatively, will it be valid to Farringdon to reduce my cycling
distance if I can't go all the way? I ask that because I am told by a
ticket holder that Cambridge-London Terminals seasons at least are valid
to Moorgate via Farringdon.

--
Colin Rosenstiel