I see what you're saying, but I'm not sure it's completely accurate. The services were told to assume there would be no major war in Europe for 10 years, and arms development proceeded on that basis. It's not so much a "colonial" mindset - the Experimental Armoured Force proved they could manage high-intensity mechanised warfare if they wanted to - but rather the fact that, without planning on a major war in Europe, what was left was basically the job of policing the Empire. Equipment valuable in that role, such as armoured cars, biplanes, and air transports that doubled as bombers (or vice versa) was completely outmatched for facing an industrially advanced, technically and tactically sophisticated opponent - but then again, it was never intended to. The problem was that the 10-year planning horizon without a major war kept on getting pushed back further and further, year by year, until it was something like 1937 before reality hit home and "no major war before 10 years is up" became "major war imminent". To me, that's more a failure at the political and strategic level rather than anything else. And, to be fair, could anyone have foreseen in 1933 what Hitler's election was going to lead to?
The other thing to keep in mind is that the 1920s and 30s were a time of rapid technological change, and what we now know as the "right" decisions were not at all obvious. Everyone was making all sorts of terrible designs and decisions, simply to find out which theories and developments were worthwhile. There was an awful lot of trial and error in that period, and sometimes the trials were not trialling enough (look at the American torpedo saga). The Americans were relying on equipment that wouldn't have been out of place in WW1, the French went big on fortifications and heavy tanks, the Japanese were learning from their China experience, Germany wanted alternative artillery, and so on and so on. Compared to what else was being made at the time, a lot of British gear actually compares quite well. They certainly weren't the only ones who had to get into a high-end war before learning what worked and what didn't.
It's interesting you pick on their readiness to face tanks and aircraft, because actually I think the problems there were not related to the equipment. The 2-pounder AT gun was one of the best in the world at the time, and quite capable of dealing with the tanks the Germans used. Similarly the Matilda II and Valentine were perfectly respectable in their roles, with what for the time counted as thick armour and a decent gun (that 2-pounder). Where things fell apart was in terms of doctrine and tactics, and the opportunity to develop these further during the inter-war years was not taken advantage of.
In the air, the same thing situation applies more or less. The Spitfire and Hurricane were no worse than the German aircraft they fought, and the Wellington was probably a better medium bomber than anything the Germans had. There was also the integrated air defense system of the UK, which I don't think existed anywhere else in 1939. Tactics and operational art were behind, but I would claim the British had a technological edge in the air war instead of lagging behind.
All in all, I would say that while the British did lag behind the Germans at the start of the war in terms of how they used their equipment, this was not because of a "colonial mindset" and certainly couldn't be described as "woefully backward" technology!