Mike, there is no hurry to be taking decisions. First of all, I suspect you are still in shock after Kemble. I think you need to take some time completely away from flying to probe how you're feeling. This will also allow time for you to recover from the effects of the accident at Kemble. How long should you take? Just as long as it takes!
Just see how you get on for a short while without flying being a part of your life, bearing in mind that it has clearly been central to your existence for decades. If possible, test out some new interests and just see if they are enough for you.
Alternatively, you could pass on your clearly immense experience by becoming a ground instructor, perhaps on a professional course somewhere. Although even PPLs or the Air Training Corps would surely benefit from what you have to teach.
Another suggestion; it sounds as though you have some tales to tell. Have you ever thought of writing about your experiences? Since the sad loss of Duke Elegant we are definitely short of a teller of amazing-but-true stories around here. It'd be nice to have a British one.
I'm a lowly PPL with not all that many hours in my log, (a beginner by your standards) but I learned to fly originally in the late 1950s. In those days, still barely fifteen years after the end of World War II and only seven after Korea, there were still quite a few of what we used to call 'shell shocked' airmen about. My own instructor was one. These were people who had seen a lot of friends killed and had ended the War feeling very much the way you do, but they were compelled to go on flying as they knew no other way of making a living.
Fortunately, you are not in that situation. You can choose whether you give up flying altogether, do something else related to flying, or carry on flying as before.
You have a choice, Mike. Don't be afraid to exercise it, but don't be in a hurry.
Very best wishes,
Broomstick.