I know you are tryin to help mate but 9 months of carp fishin is not really enough experience to draw on and you are slightly confusing things.
The fish are very clued up, i have been around long enough to know it when i see it They are also quite old, when you have been staring at the things for years you can tell. They have certainly been fished for in the past and probably had a fairly horrendous experience on the bank because it has gone into their long term memory (Carp have a short and long term memory, just like people).
They are not thriving that well, there is not a huge amount of food in there, there is no weed (except as mentioned which is not a nice sort), no lilies, a few dead trees they do like to hang around and sunbathe. They are actually quite twitchy as they have little cover from herons and cormorants, meaning they rarely sit still for long unless tucked into the bank. I am actually going to go down the shop, buy some lilies and chuck them in because the carp have nowhere to sit under at the moment but that is not the point right now. The place is not rich in food in contrast with many other places I have fished and this is likely to be why the carp have not grown that large and why they must visit the margins to feed.
If you try and fish with naturals you will find that the perch will be more interested than the carp, so you cannot sit on your backside ledgering a worm or maggots - as a stalking bait however, it may work.
The snail shell idea is very good and I will try that too.
It is, however, a very pretty place to fish and is an small, old gravel pit. The biggest fish me and a mate watched jump three consecutive times like a salmon, right out of the water. Jump, jump, jump. We got a good view, I put it around 20lb, a common. It was the sort of carp you want to catch