There is a list of aircraft requiring type ratings in LASORS; if it's not on that it's covered by a class rating.
The Turbine Islander, Defender and MSSA (?) are on the list, the piston Islander isn't (looks like it's the same as the JAA list but I didn't check it all).
LASORS is available here:
http://www.caa.co.uk/docs/33/LASORS_07.pdf , you want appendix B to section F. It's a bit big, mind (8.2Mb)