@
meldrewreborn
This probably boils down to the BOL, or Business Organisation Layer, which is the 'interface' between each individual energy supplier and the DCC themselves.
Similar to the days of flat bed scanners in the earlier days of home computing. Different manufacturers (Epson, Fuji, Canon, etc.) all had different ideas, different electrical connections (USB, parallel port, SCSI), etc. and different hardware level drivers. All the software companies who made imaging software wanted to work to a single standard so any software package worked with any scanner, regardless of hardware differences. The industry then developed something called TWAIN which was a translation layer, or interface, that allowed any hardware to work with any software.
The energy companies work like the scanner manufacturers. Different internal systems.
The DCC is setting the data standard and transport method which is similar to having a common standard for imaging software.
Each company's BOL is like the TWAIN plug-in which let's one side talk to the other, and like scanners is bespoke for each company.
Back in the 90s when PC imaging was the butter on my bread, scanners never gave me too many problems and neither did the imaging software. TWAIN was almost always the problem. Not implying that the analogy is exact, of course...
And just for gag value, the acronym TWAIN....it stood for 'Thing Without An Interesting Name'. Make of that what you will.