My GPS system went a bit weird after I reached the Knockanaffrin ridge! This route is quite steep though very enjoyable. After reaching the lough, I saw a grass ramp, on the left hand side, leading up towards a spur leading to the ridge proper. The very obvious gully leading from the lough up to the summit appears very tempting, but I'm glad I didn't try it as there are some very steep parts near the summit.
The descent via The Gap is very straightforward though extremely wet and boggy.