i layed my edging bricks on my drive with a 4 and 1 wet mix 10mm pointed gaps and they havent budged and look good too . my neigbours had the so called pros in and it dont look a pretty sight with all the bits of grass and moss growing inbetween the blocks, if i never infilled with concrete i would had probaly layed the whole drive on a wet mix with jointing ,bit time consuming but i think its more tougher and lasting, each to there own they say ,ne way good luck again
This method is fine as long as you allow for expansion (10mm joint breaker) every 6m or so.
Laying on a bed of compacted grit allows for subtle flexibility and a uniform pattern over a larger area.
This is really only a decorative edge so that the two different coloured gravels don't mix together. We may occasionally drive a car onto the main gravel but it won't be anywhere near the blocks. I did a similar thing at my last house but it was a semicircle made from flat edged blocks. If I ever get my laptop fixed I'll post a photo when I've finished. Thanks for the advice. 
