In answer to your question, OP, the standard the courts apply in assessing medical negligence claims is the same in Scotland as in England and Wales and is based on the Hunter v. Hanley test. You need to prove deviation from normal practice, viz:
"First, it must be proved that there is a usual and normal practice;
Second, it must be proved that the defender has not adopted that practice; and
Third, (and this is of crucial importance) it must be established that the course the doctor adopted is one which no professional man of ordinary skill would have taken if he had been acting with ordinary care."
Larger payouts tend to be based on loss of income through being unable to work and to enjoy a normal social life, and on ongoing medical care. Claims may be reduced by up to 100% for contributory negligence.
You would also have to prove the main or prevailing cause of your loss was any negligent medical treatment, not smoking or working in a textile factory. Did any of the non-smoking ex employees of that factory go on to develop emphaseama?
The sort of questions being posed to you on here are nothing compared to the questions that would have to be answered in court. Your diagnosis could well have depended on a number of diagnostic factors, however it has to be asked whether the time of diagnosis was relevant in the fact that you claim the damage occurred more than 30 years ago and you have been a smoker for 33 years, including after your lung scan.
The NHS is horrendously busy, and they see a lot of people who perhaps don't take the care that they could for their own health. I would have thought this sort of timescale was quite standard when dealing with that type of patient. Presumably you have been suffering from symptoms for a number of years, but it did not occur to the you to stop smoking, but instead harry the medical profession who are trying to help you (more than you are doing yourself)?
I think people on here are being harsh because there are a lot of dedicated medical professionals frustrated by people like you who would like to see this sort of thing to you but cannot; there are also a lot of patients who have in no way contributed to their own disease who have to put up with longer waiting lists because of people choosing to lead unhealthy lifestyles.