When I originally mentioned this reg on this post, I said this was fine and happens a lot, there is one reg to be mindful of, and asked the question - "can the two legs be considered one circuit".
The last bit is key, as very often they can, but sometimes they can't legitimately be classed as one circuit due to ccc or ocpd requirements.
For example, at a recent EICR I found an unlabelled 30 amp rewireable fuse, testing showed it fed a sub main to a shed and apparently strangely two sockets in a utility room. Take front off board and find a 6mm and a 2.5mm live in the same fuseholder. One might logically guess the 2.5mm was a radial for the two sockets. In fact it was yet another radial for a boiler FCU. (the utility room sockets turned out to be a joint box off the 6mm)
In that situation I had no issue citing 314.4 as one reason it wasn't adequate, the ocpd wasn't suitable for the boiler circuit and the whole lot was downright confusing. Definitely two circuits in the same fuseholder.
But if the same OCPD is needed, the same CCC, and the total loading is suitable, it clearly becomes one circuit in my mind.