The "old" DSC2 was an unnecessary addition. There was nothing to be gained by it. The important qualification was included in DSC1. There was no reason to do DSC2, other than personal satisfaction at having another certificate.
Given that the application form for the new BASC register of competent stalkers is asking for trained hunter number / LGMH certificate, and that the information states that the register is "primarily", not "exclusively", for DSC2 holders, it would be reasonable to assume that the old DSC1 would tick the necessary box for inclusion in the register, but if you've done the new DSC1 then you would also need DSC2 (or a standalone LGMH qualification).
But I would like clarification on that. Perhaps
@Conor O'Gorman could help?
I hope BASC do clarify this, but I also think it's important to distinguish between the requirement to put deer into the food chain, and being able to demonstrate competency in terms of actually stalking deer.
DSC1+LGMH was never equivalent to DSC2. I can see that it may well have been an unnecessary addition given your personal circumstances, but when it comes to the practicalities of stalking deer there remains a world of difference between the two.
The fact that the LGMH certificate was included in DSC1 was viewed by many as an anomaly, since it didn't require the DSC1 holder to have ever stalked, let alone shot, a deer and put it into the food chain. This has been discussed many times on here, and highlighted as a flaw in the old DSC1. However it did reflect the fact that the DSC1 is "a largely knowledge based qualification which enables candidates to demonstrate their understanding of basic deer management principles and meat hygiene, and to show competence in safety and shooting at simulated targets."
These days, of course, the LGMH certificate is now awarded on completion of DSC2. That doesn't detract from the fact, however, that many holders of the old DSC1+LGMH had never in fact stalked or shot a deer.
Take a look at what the register actually talks about. It speaks of "landowners, government agencies or institutional bodies looking for individuals to carry out deer management on their land."
Consider this in terms of DSC2, which requires the holder to perform at least 3 witnessed stalks, and meet the standard in terms of demonstrating "their knowledge and competence in legally, safely and humanely culling deer and dealing with carcasses hygienically."
If a landowner were to approach BASC - or indeed any other organisation - and say that their deer to be managed, which of DSC1 and DSC2 would you expect to give them most confidence? The entirely theoretical one, where they may never have actually shot a deer, or the practical one, where they demonstrably have?