Thanks A.M.
This morning I have managed to re discover a reference to Report M31 which I had made a note of on the ‘piece of notepaper’ – but of course I had forgotten to note the origin of M31 LOL and could not find a copy of the report last night.
This excerpt is from Aircraft performance data for WWI by Stephen Harker

http://sjharker.customer.netspace.net.au/WWIAircraftPerformance.pdf

Sopwith Pup

Report M.31
Date 21 Oct 1916
Engine 80 hp Le Rhône
Airscrew Lang LP.1020
Weights (lb):
Empty 787
Military Load 80
Pilot 180
Fuel and Oil 178
Loaded 1225
Max speed (mph):
Ground level.. 111.5
5000 ft……… 105
6500 ft ………106.5
7000 ft ………103
9000 ft……….103
10000 ft …….100
11000 ft …….101
13000 ft ……..98
15000 ft ……..85