Squadrongirl, you may well have resolved your problem with the Mk V by now, or even forgotten it entirely, but maybe these notes will help. The Mk V shell is exactly the same as the Mk IV, which is to say it has the Lift The Dot liner fixing, which the Mk III did not (nut&bolt fixing in the crown). The only difference between the IV and V is the liner itself. The mk IV used a liner which was essentially the Mk II shell liner with a LTD fitting. You have the typical Mk V liner, which was developed in the mid-Fifties and introduced around 1959. These were inserted into existing Mk IV shells, no new shells were made specifically for the new liners, as shells were plentiful, and commonly refurbished and repainted and given new liners and straps. You will always find a date on the liner, but that has no relationship to the date of the shell, and could have been put in at any time. Liners were changed as required, when worn out or broken. The liners (confusingly designated the Mk IV liner) were made up to some unknown time in the 1970s.
It is commonly believed - with good reason - that the Mk IV shells (also used as Mk V - are you paying attention?!?!?) were made in two or three bursts of production between 1945 and 1953. Not all helmets were stamped, and some stamped so lightly they are illegible, and others have had the stamps thoroughly obscured by repaints. Get the liner out and look with a bright torch either under the front brim or near the chinstrap bails. You might find something exciting!
Please note - we don;t know for absolute certain when production of the Mk IV/V shells ceased. Occasional outliers have appeard - recently I got this one, a ROCO dated 1956. Hard to believe, but it is true.
And, of course, just because the liner has an apparently appropriate date it does not mean that it was used in Northern Ireland.
I hope this helps. Oh, and learn to love your Zuckerman (properly, the Civilian Protective Helmet) they have their own charms and varities.
