I did a little bit of research this morning, but to no avail - the Southeast Communities Rail Partnership website doesn't actually have anything about this on it, and the most likely link doesn't actually have anything about rail link buses on the destination page!
The road layout will be the issue there - it takes something like 90 minutes, single-deck restricted, to do rail replacement between Tonbridge and Redhill, easily more than double the time of the train. I wonder if the Parish Council have got something twisted, and it is bus links to stations along the Tonbridge - Redhill & Crawley lines being referred to, rather than a bus between the two locations?
The other mention at Cowden appears to relate back to something that was first raised to a councillor last summer, according to Parish Council minutes. There have been discussions with Sevenoaks District Council and Kent County Council since, but there was nothing to report at April. Minutes of last week's meeting are not yet available.
Chris