It's always really hard accepting the difficult truths, but your DS is having a shit time with GSCE History because he doesn't have the natural aptitude for it, and he's not putting in the work to try to compensate for this. As he's not putting in the work, he cannot be as interested in it as you/he thinks he is, and you're just throwing good money after bad.
Your DS being bad at history is not the end of the world. There are very few jobs and career paths that require excellent history skills - he has so many options still open to him! How is he getting on with his other subjects and extracurriculars? Are there other areas which you can encourage/nurture more?
Your DS's school teacher is apparently to blame for why he can't take notes in class and is failing. Your DS has burned through two bad tutors. He's onto his third bad tutor. That's four adults who specialise in history at a far more senior level than DS who have been unable to teach him properly.
At what point does it become obvious it's not the teacher and it's the child?
Money can help give certain advantages, but you cannot fix everything with money.
If you had a million pounds to spend on extra tuition for me (thanks!) then you'd still still never get me to do a simple cartwheel. Everyone has their own limits, and it can frustrating when those limits are below our own limits, and our own expectations.
DS is fine being bad at history. I'm fine not being able to do a cartwheel.
Your DS has been hugely disorganised, distracted, and failed at learning through standard techniques... so I thought I'd just ask if he had shown any indicators of neurodivergence? If he's only struggling with one specific subject, the symptoms here are almost certainly symptoms of Teen Boy. But if there any other issues elsewhere in his schooling or personal life, undiagnosed neurodivergence can explain why something simple is apparently unteachable.
I've tutored neuroatypical students before and transformed failing students into passing students simply by changing the study methods. The methods I've used with them have not been methods any other tutor has recommended, but they've worked.
But if your DS is doing fine in every other subject, it's unlikely that he is being let down by traditional learning methods that don't work for his brain. I know MN is very anti the existence of neurodiversity, but some people are neurodivergent and they are just as bright and capable as neuroatypical people, but need to have their learning reframed in a very slightly different way.
Incidentally... I'm not sure cricket three times a week is important if a boy is tanking a subject. Unless, of course, he has has a huge amount of energy that needs to be burnt off for him to cope... in which case, I refer to my neurodiversity question mark.
You haven't said enough for me to think it's a real possibility, but in grasping at straws for an explanation, it's the only one left I can see.
I hope you don't think I'm being overly harsh. You clearly love your DS and want the best for him - you wouldn't have persevered with three tutors otherwise, or ferry him around to extracurriculars - but I do think there is a mismatch between the life you want for your DS and the life that is right for him.
Trying to push a non-academic kid into academic success is not as supportive as you might think. Far kinder to help him find what's right for him and encourage that.
If he is actually good at cricket, he probably is pretty good at teamwork, and that's a far more useful life skill than being able to remember the dates of some random war.