Use Google Earth or Google Maps (Satellite View) and look approximately 500 metres from the listed coordinates of GC3BK98 They Went Ata-Way! for the name of a romantic painter:
His Birth and Death dates were AB C DEFG and HI J KLMN
To find where the cache is hidden complete the following calculation.
South 34 F(K+L).EDM East 138 C(A+C).(H+J)GI
(BODMAS is not applicable)