I completed this puzzle in around 2 hours. Shocked the grey hairs off me, I can tell ya, but I did it.
Puzzle 85, however, I've been staring at since 12 April and didn't get a move until yesterday and that was after a lot of help - from the same man, or woman. Obviously it just depends on the puzzle and what your blindspots are.
Amazing...I joined the forum specifically to post the same query, and I see the grid reproduced at the exact same stall-point that I've been at for a couple of days. How about that! And the solution is so obvious (after it's been pointed out, of course).
Thanks to everyone for showing me the light. Nice to know I wasn't the only one stuck on #86.