Although I rate my chances of getting this answered low, I thought I'd ask here.
In 2005 +- 2 years, I stumbled across a novella (might have been 100 pages in length) that was available online for anyone to read in full.
Author: Not a professional sci-fi writer, possibly not even a published writer in any genre. In a bio note, he said he was recently retired, had traveled the world in a variety of jobs including government service, and was British (or maybe South African), in any case not American.
Style: Deceptively simple, possibly the un-flashiest SF writing I'd ever seen. At the same time, avoided all the pitfalls that novice authors fall into. Sentences flowed, story moved along smoothly. Little use of metaphor. Philosophical musings refreshingly absent. Author does not get in the way of story, at all.
Plot: Ah, here's where my memory sadly fails me. I'll try to piece together bits and pieces of the narrative.
Starts in a holiday resort in East Africa (Kenya? Somalia?) While the narrator is on the beach barbecuing, someone tries to kill him and barely misses. Retreats to levitating vacation home (anti-gravity apparently has been solved). Seeking answers for who wants him dead and why, travels to Jerusalem. Population now ten times of present, apparently under UN administration. Decides to sign up with military. Is shipped to Mars.
We learn that he is several hundred years old, and due for a total body replacement soon. Appears to be independently wealthy but not super rich. On Mars, gets into a tight spot and finds more questions than answers. Possibly a plot by a subversive faction to wrest power from the current one-world government. Moves on to outer solar system, to a moon of Jupiter (or Saturn?) where he is again nearly killed in the frozen wastes of the moon but escapes with his life. Enemies vanquished, he returns to Earth. Final scene is in a glitzy restaurant in a satellite orbiting Earth, where he and girlfriend (wife?) toast his success as stars twinkle through the glass roof and city lights blink from below.
Was never able to find that novella again. Possibly the author had put it online in hopes of attracting a publisher, then withdrawn it when no one expressed interest.