I can highly recommend the 4 part BBC doco series, FINEST HOUR made in the 1990's , it details the 1940 battles very well with first hand interviews with veterans .
https://www.amazon.co.uk/Finest-Hour-DVD/dp/B000JLTE98
I recall they interviewed an ex-British armoured regiment recce officer. His comments were something like this.
Here is 21 year old me leading the whole regiment to where the German armoured columns were advancing. Within ten minutes our regiment ( equipped with Matilda 1 tanks ) was almost completely decimated . My tank managed to escape , at night we crept into a German column of transport, our black berets looked similar to the German tankers berets ! We actually rammed the truck in front of us accidently and a tirade of German swear words came on.
After abandoning the tank, he and his driver attempted to swim a river but the driver drowned . The doco makers go to an abandoned villa where the pair tried to rest , here is where the driver carved his name into a wall and its still there today.
They also interview a British corporal, who was in charge of a mortar platoon behind the Dunkirk beaches , this chap describes how a mixup in orders had his men send a a mortar barrage over onto their own chaps , which caused mortal casualties.