In response to anyone who feels rather dumb, as I did in pushing an SD card into the CD/DVD optical drive, entirely as a result of not concentrating and applying 'more haste, and consequently less speed!'
.....Here's my solution!
Hastily, tried the improvised double thickness cardboard 'hook' technique from a Marks & Spencer Lasagne sleeve! and ...Failed!
Didnt fancy the Apple Genius route for fear of looking a complete elderly fool walking into an Apple Store in a busy shopping centre with a 27" iMac testing my balance, asthma, and upper body physique! Guess that would be hashtag 'notcool'
Didnt fancy the Apple Genius route for fear of not knowing what it would £cost!
'L' shaped Paper clip seemed to be a very successful solution but was put off by the idea of doing anything that involved carrying my iMac down a flight of stairs and tripping up on the penultimate step by Charlie the cat, solely in order to place it face down on a table, or sit with it on my knee exascerbating sciatica!
Also didnt fancy pushing metal into 'the abyss' for fear of potentially causing damage!
Read the post about inserting a 150mm/6" inch ruler diagonally, but sadly my redundant Civil Engineering Scale Rule was too thick!
Then, hey presto! I noticed I had two unopened SanDisk products, a Cruzer Switch USB flash Drive and a SDHC Card each mounted on card packaging 125mm x 75mm and 1mm thick. I firmly hand held the the two products' card packaging back to back and inserted/guided them into the optical drive at a 45 degree angle until the packaging contents would not allow any further intrusion. On both products the item is packaged at 72mm from the top edge.
Voila! As I pulled the double packaging away from the optical drive, still at a 45 degree angle, my relief was ecstatic at the sight of a blue corner of a 2Gb Integral SD memory card, appearing from behind the 'Stage Curtain"
So there you have it! ...I could have condensed this to:
Dont bother unplugging your iMac. Ooops safety first!
Dont bother balancing it on your knee as if it's swallowed it's tonge!
Just get a piece of smooth cardboard minimum 72mm high and 75mm wide and insert it at a 45 degree angle, pull back, and feel the 'resistance' of the lost SD card, and firmly pull until it appears!
I genuinely and sincerely hope something similar works for you too, as the satisfaction in obtaining a solution is 'Epic'
Thank you also to everyone who bothers to contribute to these forums