Yeah, I think it's more "advisory" rather than law therefore, as with a lot of folk "advisory" info often differs from law, which is why my kid does not go to school in uniform (tesco crap offering no quality, cold, polycotton, shrinkage, dubious sourcing & labour...
instead she dresses for the weather & tends to wear harder wearing fast drying kit such as Lowe alpine fleeces adding / removing a layer accordingly, ..really annoys her school who occasionally have a teacher bully her about it, ((stupid & unnecessary)).
Therefore re the blood, probably makes life "easier" for H&S et al at our loss & have to import
FFS!
but without being an actual requirement legislatively, thus "the few who do" & the bit on you-tube of real "fresh & chilled" blood used for janet street porter's bit on that Gordon Ramsay show.
All depends how far you are willing to read, deduce, comply at the end of the day.
From my point of view dried is clearly more convenient, but with the clear upsurge of interest in black pudding I find the import aspect reprehensible, ..give a uk firm / abbatoir a chance to diversify & make some profit in a country where animal welfare is markedly better (on the whole) than elsewhere, whilst contributing to uk coffers.