1. Sleeprider deserves to be raised to knighthood or some kind of medal or something. The man is a hero and a living legend, who has helped untold number of people with their apnea. I'm not kidding. Thank you, Sleeprider, for all that you do.
2. OP really should pursue the NHS route. Maybe it'll take a while, but once the gears are in motion he'll at least get access to a steady supply of ASV machines, for free. There will also be a paper trail of effective treatment, which might be important for insurance purposes further down the line (mortgages or life insurance or whatever which might require a medical checkup).
3. If you have a bed partner who tells you that you're not breathing, or that you snore loudly: get tested and get treated. Don't shrug it off. Deal with it. The sooner, the better.
4. CPAP doesn't have to be unsexy. I really don't understand why virtually all CPAP pictures include full-face masks with bulky headgear. The vast majority of CPAP users can get by with nasal pillows with minimalist headgear. Using those pictures instead would reduce the anxiety people feel about getting on CPAP. [1]
5. AHI is a largely meaningless number. "Mild" apnea can be just as devastating as "severe" apnea. AHI only looks at events/hour, it doesn't look at when the events occur (e.g. during REM), how many are back-to-back, and how much your sleep is actually disrupted. You can have a "normal" AHI of 5 and still get absolutely trash sleep because of un(der)treated sleep apnea.
[1] Nasal pillow mask: https://www.resmed.com.au/healthcare-professionals/products/...