Lance, the gauges are not the same.
Cromwell is an 87PG/240 where the tube is 240" long
Humber Scout is a 97PG/192 where the tube is.......192" long.
The 87PG gauge is 0-160 PSI and the 97PG is 0-100 PSI but some illustrations show both and frankly, either would work fine. Out of interest, Centurion ARV uses a 87PG/312 and is a potential source.
Obviously, the longer tube will work in all installations.