Further to my post above, after extensive discussion, Nokia have now agreed to refund the full purchase price of each of my Nokia N82s, because of my complaint about the missing ALS function.
Not bad really: I paid HKD4400 for each phone (the current price is HKD3800); once I have received the refunds I can buy N78s as replacements. The N78 does have ALS function, is a bit less chunky than the N82, seems more up-to-date than the N82, and (best of all) is retailing at only HKD3500.
But I won't be updating the software in a hurry.
By the way: as of today, Nokia's FAQs at
http://europe.nokia.com/A4577229#faq17 still categorically state that the software update will not affect the ALS service. I have suggested to Nokia that they change that statement, to save other customers having the same bad experience that I did.
Also they will probably need to amend the N82 User Manual, and brief their staff that the N82 no longer supports ALS (as recently as last week, Nokia sales staff assured me that the N82 supported ALS, and were most surprised to find that it didn't). Could there be some misselling happening out there?
Finally, thank you to all those who read my original post and who offered advice.
5800XM (RM356) V21.0.101; N95 (RM159) V21.0.016; N82 (RM313) V31.0.016; N79 (RM348) V11.049; 6233 (RM145) V05.60