AiM9Ls
Wiggy
We'll just have to agree to disagree about when the 9L came into RAF service unless someone in Air Def at the time comes up with a definitive answer.
However, notwithstanding what the STCAAME boffins said to you - and some of them were pretty good at the bull**** baffles brains bit - I am fairly sure about the background to SWIFT. Also, it was never used on the 9L (no need), but was indeed a module which went into the redundant space for a US-type coolant bottle on the 9G. Earlier versions of the AiM-9 also had this coolant bottle space, or at least the 9B did; I know 'cos I flew wirth 9Bs strapped on quite a few years ago.
For BEagle - I can't remember now exactly what the acronym SWIFT stood for, but like you, I have a recollection of what it did and how it achieved its aim. But I don't think we need to elaborate on that in this forum!
Finally, for Wiggy, thanks for your PM.