During Potter's recollection with Lill of doctoring during WW2, he refers to an incident which happened before D-day when a soldier took his girl to the beach at Brighton on England's South Coast. He tells how their tryst was interrupted by lights and soldiers practicing for D-Day.
I lived a few miles west of Brighton from my birth in 1943 and can attest to the factual inaccuracy of this section. Brighton was towards the western end of the section of the South Coast that had been regarded as likely landing grounds for the Germans since 1940. Access to the beach was denied to all and even the approaches to it were mined. Our house was about half a mile from the beach and I damaged many front wheels of my bicycle riding into the holes left when the minefields were eventually cleared.
Nor was the area used for large scale invasion practices which were generally held further west in Devon and Cornwall the beaches of which more closely resemble the Normandy beaches.
Finally, in the period leading up to D-day most troops of all nations were confined to their camps. This wasn't just a security precaution but logistics also; there were so many soldiers assembling in these areas that local facilities would have been overwhelmed had the soldiers been given free access to them.
I realise this is a fictional series and the inaccuracy didn't diminish my enjoyment.