The maritime squadrons 201 or 120 would be sensible. 201 because it was 1 Sqn RNAS and became 201 on 1 Apr 1918 or 120 because of its special circumstances in the award of its standard.
I've reformed a couple of units in the past and by far the hardest and most contentious thing was the number plates because everyone seems to have a vested interest and everyone has an opinion. Everyone's opinion is the correct one and causes hours of nugatory staff work.