When the RAF harriers were built the aircraft with the "ZD" serials wewre fitted with the 65% LERX and the "ZG" serialed aircraft were fitted with the 100% LERX from new, there was no up-grade up to the 100% LERX for the Batch 3 jets.
By the look of the photo I waould say that it was taken about the time that the RAF Harriers where flying Op "Warden", the no-fly zone in the north of Iraq after Gulf War 1 whn all the jets assigned to the operation where fitted with the smaller 65% LERX.
it was proposed to fit the 100% LERX to the "ZD" jet in the JUMP program by this was cancelled to cut costs.