(2) Save in accordance with a collective agreement negotiated with any recognised trade union or staff association concerned, a person referred to in subsection (1) shall not, while in the service of the services subsidiary or other subsidiary, as the case may be, be subject to less beneficial conditions of service (including conditions in relation to tenure of office) or of remuneration than the conditions of service (including conditions in relation to tenure of office) or remuneration to which he or she was subject immediately before the staff transfer day.