I have a Korum chair which can be set as high as a seat box. It's the best chair I've ever used and has a back rest.From a seat box, modern chairs are too low, being comfy on a seat box makes all the difference.
Spot on mate!standing doesn't scare the fish at all. Only recently I've been catching barbel / chub etc that have followed my loose feed at the end of the rod tip. Many times I've had barbel amongst other fish species jumping within 3 or 4ft of me when standing mid river totally unconcerned about me being there.