Article 5, of SI333 of 2000
"5. (1) Subject to the provisions of this Order, a person shall not act as a flight crew member of an aircraft registered in the State unless that person is the holder of an appropriate licence issued or validated by the Authority, or a JAA licence.
[...]
(10) For the purposes of this Article, a valid and subsisting licence, other than a JAA licence, issued by any other state which is a member of the International Civil Aviation Organisation in conformity with Annex I (Personnel Licensing) to the Chicago Convention purporting to authorise the holder thereof to act as a flight crew member of an aircraft, not being a licence purporting to authorise that holder to act as a student pilot only, shall be deemed to be a licence validated by the Authority under the provisions of this Order entitling the holder thereof to fly as a member of the flight crew of a private aircraft3 insofar as the holder is permitted to do so by the terms of the licence and by the law of the state by which it was issued:
Provided that-
(i) the holder of such a licence shall not, for the purposes of this Order,
exercise any privilege relating to instruction in flying or flight under the
instrument flight rules which may be attached to the licence unless
otherwise so entitled under this Order,
(ii) if the Authority sees fit to do so, it may at any time prohibit the holder
of such a licence from exercising the privileges conferred by this subparagraph and, in that event, such licence shall cease to be deemed to
be a licence validated by the Authority under the provisions of this
Order."
If you have a valid licence for that class/type of aircraft, and are currently, and the licence is ICAO compliant, and you have an ICAO medical, then you don't need to do anything else
dp