The Naval officer on the Landing craft had a moustache. Moustaches without a beard are not permitted in the Royal Navy.
The GTN tablets given to Irene for treatment of her angina are incorrectly referred to as glycerine tablets. A doctor would normally refer to them as GTN tablets or might possibly as glycerol-trinitrate - but never glycerine (which is something you put in cakes).
There is a mispronunciation of dossete box. The standard pronunciation used by medical professionals is dó-sit, with the emphasis on the first syllable, the 'o' like the o in orange and 'sit' like the word sit. It would not normally be pronounced to rhyme with cassette, as in the film.
While on Sword Beach in the evening the sun is setting to the right of the screen. This is the east.
The military cemetery shown was not Bayeux as stated.
The bus (supposedly in Hove but filmed I'm Hastings) said Dover on the front. Dover is 2 hours drive away and the ferry goes to Calais, a long way up the coast from Normandy. Newhaven ferry terminal is only 12 miles from Hove and goes directly to Dieppe in Normandy.
When Bernie and the Germans salute each other in the bar, Bernie salutes in the Army/RAF fashion - palm outwards. As an ex-Navy man, he would've saluted in the RN style - palm downwards.