To set things straight:
ZM135, 136 and 138 are all instrumented for Operational Test and will go to 17(R) Sqn.
ZM137 will go to 617 Sqn.
All are LRIP aircraft so built to exactly the same standard as the others in their batch.
ZM135, 136 and 137 are all at Eglin as pooled assets for training, prior to the start of OT.
Whilst the early Development Test jets from Edwards and Pax River may get retired in a few years time when their mission is completed, the UK jets have got years of life ahead of them. The principle point of the current Main Gate 4 is to buy the operational jets for 617 Sqn and 809 NAS in due course.
Does that clear things up?
