The British might have been tempted to blame their poor performance prior to July 1942 on the need to send forces East to deal with the Japanese attack. The truth seems to be that their real troubles stemmed from a combination of factors. First and foremost was that they lacked competent leadership from the army commander level to at least the division commander level. General Auchinleck, despite his failings, probably could have commanded the 8th Army successfully in the field. That is what Churchill begged him to do, but Auchinleck felt that his role should continue to be solely as theater commander. In critical situations, Auchinleck stepped in and salvaged the British cause, such as the Crusader Battle and after the fall of Tobruk. He then would step back out to theater commander.
General O'Connor, if his health had not failed after the successful campaign against the Italians in late 1940 and early 1941 was probably the equal of Rommel, but his health did fail, and then he was bagged by the Germans when he drove forward in western Cyrenaica. No one who remained, from the theater commander, General Wavell, down to the division commanders, was up to the job of fighting the Germans.
The Germans had good doctrine, well-trained officers who were extremely competent, and had second rate tanks, not much better than the British but much more reliable than any the British had except the American-made Stuarts. They did have superior anti-tank guns and the doctrine about how to use them. Nothing could stand up to the "88", or even the 50mm PAK38's.
The British continually made fundamental mistakes that never should have been made by experienced officers. They continually dispersed their forces, especially the armoured forces. They broke down the infantry divisions, as well. They were always used at this stage of the war as a source of independent brigades. The brigades were often broken into battalions and dispersed into battle groups. The British thought that they were copying the Germans by having these small, independent groups, but they did not really understand what the Germans were doing. The British habitually committed the beginner mistake of trying to have small forces "everywhere".
I hate to say that I agree with Bernard Law Montgomery on something, but he was trying to counteract the dispersion by decreeing that "divisions will fight as divisions". He also disliked the "Jock Columns" because they were just another means of dispersing forces.