3. The BEF had already proven the British could fight better than the Poles, the French and the Russians whilst on foreign soil. The idea that the British would then fight worse whilst on home soil is somewhat bizarre.
There is a British smug complacency about the performance of the BEF in 1940.
For a start the BEF faced the German feint into Belgium rather than the main armoured force, so claims that the Germans never broke through are meaningless. When the BEF did have to fight it it did not do particularly well,except in dogged static defence.
Much of the BEF was ill trained for mechanised warfare. Wireless sets were in short supply and training curtailed for fear of compromising security. Few units or formations were able to communicate by wireless or practiced in long moves (Montgomery's 3 div the exception) The Arras counter attack was a shambolic affair , marked by a lack of co-operation between arms and the loss of most of the attacking armour. Yes I know, that even as a tactical failure it disproportionately worried some Germans. But it was an example of how not to mount a mechanised manouvre.
The BEF was ill structured and under equipped. The country that invented the tank did not have an armoured division in France until after the German attack - and then it was frittered way. The 12th and 23rd infantry Divisions were hastily deployed across the old Somme battlefield against the Panzer spearhead,where, lacking anti-tank or other heavy weapons and artillery they were overrun. The excuse is that these were labour battalions that should never have been used as infantry. But they serve as one marker of the fate of the LDV or under equipped post Dunkirk Home forces units.
Tactically the Germans were better trained to co-operate in the uncertain chaotic conditions of warfare. With few exceptions it was the Germans who seized the tactical initiative in every engagement. Even on the Dyle and Escaut canal the non mechanised German infantry held the initative against British formations lavishly equipped, by 1940 standards with light AFVs.
There was a similar pattern in Norway where the Germans out manouvred the under trained and ill equipped British. The proof of the pudding is in 1) the Batholomew report which was quite scathing with respect to British shortcomings. 2) the subsequent development of training in Home Forces.3) the widespread lack of confidence in the British Army shown by some of the most talented junior officers into forming their own private armies - commandos - LRDG - SAS- Paratroops SOE . Read their memoirs. They were embarrassed by the Blimpish Army.
When you use the term "fighting worse" I think you mean has lower fighting power. This is a combination of the physical, conceptual and moral components of power. I don't think anyone doubts the courage or fighting spirit of the Tommy, but guts goes only so far against an enemy out manoeuvred them or used weapons to which they could not respond.
That was the story of British reverses from Norway through France Greece,Crete North Africa and the Far East, Under trained under equipped troops deployed expected to make do and muddle through against a better trained and equipped enemy. The post Dunkirk Home Forces were in the same position. Would they have fought more bravely than the Poles who rode horses against machine guns? Or the French that fought to the last? No one will know.