Where a member’s contribution under regulation C2 or C3 of the 1986 regulations in respect of a period including 31st December 1992 was based on a remuneration which, for the purposes of the 1986 Regulations as in force at that date, included an amount representing the money value to him of the provision of a motor vehicle, then the money value to him of the provision of such a vehicle shall be treated as included in his remuneration for the purposes of these regulations until the earlier of—