Disclosure- I'm not a fan of forced symmetry.
In my own photography it's something I fall back on when the elements in the shot don't seem to be coming together. And about the best thing symmetry can do is highlight a jarringly non-symmetrical element somewhere. Unfortunately the random dags of seaweed on the pier in #3 aren't interesting enough to have pointed out to me.
Having said all that, #1 is a bit of a sleeper. There is a lot of interest in the shot if you persevere with it, and small low res pics on-screen doesn't encourage that sort of lingering gaze. There is plenty for me to enjoy in the shifting perspective of the blocks, the subtle shadow details in the stained wall and the massive looming presence of the thing which is well enhanced by the severe cropping. I just reckon a strongly asymmetric viewpoint could have been even stronger...
EDIT- ..stronger...
or not. It's still growing on me just the way it is. (And I echo the 'Becher' comment of Peter's)
#2 is potentially a lovely shot. I like the mood of the weather. I like the ribbon of water that leads you past the building and into the midst of the image. I can see you've printed the clouds into play, which is good, but I still don't think the top half is working hard enough. Maybe re-shoot with the tall tripod, ladder and a wide lens? You could push the horizon up much higher and open up the fingers of rock so that they really push forward out of the shot towards us. At the moment it feels a bit rule-of-thirds-predictable.
Nice work Leon. You set a high standard here, and while I can always make with a glib comment about improvements
( Oh Leon- next time you really must remember to build a 5 metre scaffold to shoot from, drain the bay and replace it with sparkling Periere water, and repaint the cottage before you shoot) 
but you know these are already top shelf pics.
