Across the 2b and 2c ranges I had to pick the B&G examples very carefully as there is a mix of OHE flash panels - some have the early type (single flash) as originally applied to the stock when new, and is therefore correct for late 1960s thru to early/mid 1980s (the era I wanted). For these, they'd also be correct for the region to which they were originally delivered (WCML).
The later style 'double flash' OHE warning panels became standard from 1978 onwards I believe, but of course it would have taken some time for rolling stock to be updated, so the B&G coaches which have these would probably be correct for early-mid 1980s onwards. The earlier OHE panels would work for this later era as well as there would have been a mix of both in use for some time.
I got caught out with M19536 SK (ex FK) as this has the early style OHE panels but as posted earlier in this thread, the conversion was done from May 1985, so it's not correct for a 1970s situation. It's a bit of a minefield getting a consistent rake together for the '70s era because of these details!
Accurascale have done a fantastic job and over the course of time I'm sure further runs of Mk 2b/c stock will be made available in order to build up consistent rakes and fill in gaps (for example, no Mk 2c B&G TSOs with early OHE panels in this 1st run yet). I also just had to add the NSE TSO (T) & IC BFK, as with their Class 50, I started with a single early BR blue D423 and then ended up bagging an early NSE and Railfreight General example as well, they just look so good in those early sector liveries. These guys are pretty addictive I'll have to admit 😅