just need to tidy up the end of the wall in the pic below, easiest way please :-)

 

 

oh and no i didnt do the cutting :-)

Could you define easy and tidy please. 

 

Quickest and cheapest way I would say is to render it but it might take a few hits to get it straight

Fast growing climber. 

Two plumb bits of timber each side and fill with a render mix. The timber will give you a guide to keep it nice and straight. But as above it will take a few goes to get it on and not fall of. Wet the wall before each attempt.

Cut it again? 

Put a post in and fill the gap.

taking comments above, how about:- nice timber post on the end, fit a sacrificial bit of wood at the back, bridging gap between post and existing wall (wouldn't be seen when finished) and then gradually fill gap with render

48 minutes ago, Temp said:

Cut it again? 

that would be an expensive option as would have to get a trade in, ime not cutting that thick a wall :-)

Leave it until the rest of the work is done, then take a view as it may get damaged or it may be OK as is.