WW2 Grey / Green Brodie Helmet Dated 1940 Possibly Royal Navy with partial Decal

Original WW2 Brodie Helmet Dated 1940.

With original grey green paint.

There is a partial stamped decal on the front with 2 lines - the top row is very hard to make out - the 2nd row appears to read  SB ORN

The decal may possibly denote that it was a Royal Navy helmet

With original elasticated WW2 chinstrap.

No date visible on The shell.

The liner is faintly stamped JCS and very faintly stamped 1940

No liner size is visible but it is quite large eg 58-59 in modern measurements.