An alternative that is used in International matches and nowadys also with the MLAGB is to have a score keep allocated to each target. So....
Rifleman 1 fires while rifleman 2 is loading
Butt marker scores target
Score keeper on firing point agrees score with rifleman and records it
Rifleman 2 fires while rifleman 1 is loading
Butt marker scores target
Score keeper on firing point agrees score with rifleman and records it
Rifleman 1 fires while rifleman 2 is loading
Butt marker scores target
Score keeper on firing point agrees score with rifleman and records it
....etc....
The person manning the target never needs know who is shooting.
This also works with 3 people to a firing point. Those at Bisley are wide enough for 3 shooters (and 4 at a squeeze) to leave matts scopes etc. on the firing point. Other ranges may have different constraints.
Come over to Bisley next sping and shoot with the MLAGB as a guest (or join) and see how easy things run.

We already have shooters from France, Holland and sometimes USA who have joined the MLAGB and shoot with us.
David