In addition to local bus services, Diamond South East operates the Hallmark luxury coach and corporate cars business, which was originally founded in 1913 as an independent company known as Flights Hallmark.

[4] Flights Hallmark bought the Surrey Connect business, which became part of Rotala shortly afterwards.

Hallmark operates bus route 458 in Surrey, which links Kingston-upon-Thames and Staines-upon-Thames.

They won the route from Oxford Bus Company in a recent tender renewal for Oxfordshire County Council contracts [8] This service ceased running on 11 February 2023 and will be partly replaced by service 24 operated by Grayline.

Hallmark currently runs buses and coaches from a number of depots in various parts of England.