Bridget —, British artist whose works include 1963 painting Fall (5)
I believe the answer is:
riley
(Other definitions for riley that I've seen before include "The life of --- is carefree" , "The life of - is luxurious" , "Op art painter" , "figuratively associated with 16 [THE GOOD LIFE] ?" , "22/26 [COUNTDOWN] number-cruncher" .)