What is the difference between to go for a walk and on a walk? Is there any?
Same thing really, just used in differennt circumstances, so for e.g.
Right dad, im going (FOR a) walk. - this is what one would usually say, and when they are about to go and do it.
Dad, im gonna (go on) a sponsered walk - this would be used in that context, meaning you're going to do it.
Hope this helps