Top marks to you there,how did you get stone up there then? Did you put some scaffold across?I dont think you"ve walled overhand when you got to ground level,it"s to tidy!View attachment 409148
Doesn't look like much now but that is 6 weeks work. For some scale that tunnel is 8 foot diameter, all rebuilt from scratch. Don't usually use mortar but needed it in there due to the force of the water