I think it always worth repeating that, due to the way the Defence budget was constructed in the mid-late 70s, the RN (FAA in this case) understandably committed to a series of major procurements simultaneously.
Just as an example, at the outbreak of hostilities in 1982, Lynx, Sea King and SHAR radars were still in development. Sea Spray, Sea Searcher and Blue Fox, respectively. Orders were issued to shut down development and launch production, regardless of design maturity. Sea Spray was the most mature, and production was “simply” ramped up. But Sea Searcher and Blue Fox still had about a year to run on main development.
In the case of SHAR/Blue Fox, 6 of the 8 B Models (which belonged to MoD(PE), not the FAA) were delivered and fitted. These 6 were roughly compatible/interchangeable, but definitely not production standard. The remaining 2 were too different and would have been dangerous to use. Training in their use was minimal. Some design features hadn’t been included yet were in the training manual, and vice versa. What Sharkey and his mates did with this immature design was nothing short of incredible. I’m not sure this minor, but quite important detail is well publicised, but it explains much. The most incredible fact was these B Models stayed in service for over 8 years, before being returned to the factory for the Mid Life Upgrade. This is a great testament to the quality of design and reliability.
In all cases, a Continuing Design Services (CDS) contract was required, to finish main development, incorporate and modify. Sea Spray was minor, although important to reliability, but the RN was denied funding and the Dutch reaped the benefit. The final year of Sea Searcher development was spread over the next 10 years as a “savings” measure, and to this day there are switches on the Controllers with no wiring behind them (a long time source of frustration and numerous MF760s). Most of the CDS was done on the quiet, behind the beancounters’ backs. Blue Fox was the one that was properly funded, progressed and completed to a reasonable timescale; partially due to the Blue Vixen development work that had commenced. This resulted in a major upgrade in 1984 (the “Jamming Package”), then the Mid Life Upgrade (I/A). It was widely regarded as best in class, and despite a 35 year old design would probably still be a viable piece of kit for many potential users. When it was eventually replaced by Blue Vixen, it still exceeded the best spec the RAF could dream up for the Bucc replacement!
Kind of puts the old “Blue Circle” balls in context!