I'm adding to this very late in case anybody, like me, is looking for advice at a later date.
I had a gastroscopy yesterday and was expecting it to be as described above. However, I DO remember quite a lot about the event - including the fighting to try to remove the thing from my throat! I was kept in rather longer than expected, too, because my blood pressure had risen so much during the procedure. Goodness only knows what I would have been like had I not opted for sedation!
Now I'm 24 hours after the sedation was given and am still feeling somewhat woozy. I'm not driving today - wouldn't be safe. This could, of course, be psychosomatic, but I'm not prepared to risk it.
My advice, therefore, is to take the sedation and then follow the advice - the experts do know what they are talking about!