In all my years collecting and visiting various militaria sales (both online and in person), I have never come across any of the helmet transfers that were made during the war. The below advert from a company called Display Patents Ltd details their wares. Amongst the items are various transfers for helmets.
Of interest is the list of 'shoulder flashes' (usually called shoulder titles). I've not (yet) seen an example of "Ambulance Driver' or "Equipment Officer" being worn.
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