Nice to see Cornwall come up there.
Your photos show pretty much the view from my bedroom window when I was growing up. I live in London now. Win some, lose some.
I agree, not enough light. I'm guessing you took these a month or two ago as it doesn't quite look full summer light (tho you never know with british weather).
The castle photo would be a candidate for HDR, as then you could bring out the murky castle. It's difficult to get the castle properly lit, as on that beach, you're facing south, so the sun will always be more or less behind the castle.
A tripod would have really helped with letting you have longer exposures without blur.
If no tripod (and I don't often take a tripod to the beach myself!) prop the camera on a wall or on some stones or a pile of sand, set it for a shutter delay, (2 secs or whatever), get the framing right, press the button and back away. 2 secs later it'll take your photo with zero blur. I do that quite often
Another tip is to zoom into the castle/island, take a photo, let the auto work out the right settings for the castle, then zoom out to the framing you want , and re-apply these settings. You might get blown-out sky, but that's the choice you make.
Addendum - you could have walked over to Newlyn and taken a pic from the pier / pebble beach there. It's an interesting visit in its own right (lots of lovely cornish cottages) and the morning sun would be behind you.