Re: But... but...
why the UK can't just reuse this code is unclear
As others have pointed out, a bad case of NIH syndrome and Brexit.
After all, as a Proud Independent Seafaring State[tm] whose governing class appear to prefer ideology over reality, we can't go using the same stuff as those filthy forriners, can we? On top of that, it means that we can't give the job to our mates without going through all that tedious competitive tender stuff.
Taking back control, innit?