I don't have experience in hiking or camping in England or Scotland, but after reading the first two answers, I want to offer a "Best of Both Worlds" way of thinking about your question.
First, unless you have left something out of your question, you don't need a six pound tent. Consider buying a smaller, lighter tent that will still give you good protection in bad weather, as @noah said. Second, don't use, or even erect, the tent unless the weather is bad. This means that you have to carry a tent which you may not need, but assuming you are young and strong, this is not a big deal.
This is the what my husband and I did over many years backpacking in the Sierra, the Rockies, Hawaii and Shenandoah. We never slept inside the tent, or even erected it, when the weather was good, but we could retreat to it when the weather was bad. Not sleeping in the tent, but having it, gives you what @Chris H calls "the level of subtlety for wild camping", without the "subtlety" progressing into outright masochism.
In our case, we could pretty much count on sun the day following even a drenching downpour or heavy snow. (Late spring, summer, early fall).
We did do one trip with a shelter thing, whose name I do not remember, which was no more than a large plastic sheet. Horrible night. Never again. But the sun came out the next day!