Luke,
You'll certainly not have anything other than support from me if you "harvest" a few trout responsibly. It seems strange to me that some people will shoot deer, birds, rabbits etc, but are aghast at the thought of killing a fish. Oliver Edwards once described to me the experience he had of fishing a famous and popular C&R only stretch in the States. He had to use flies of size 24 or smaller to get a take. This wasn't because they were appropriate to the hatch, rather the fish had learned not to trust anything larger. As a result the fish were like snakes, emaciated and starving. I understand that this is an extreme example. What it shows is that either approach taken to an extreme has a negative impact on the fish.

Here we have very different access rules for the water. Although it does provide a level of control over the number of fish taken, I would not, in any way, recommend it over your system. My argument is for the self imposed discipline of not damaging the resources we have. Though how we as anglers achieve this on mass I don't know. Until we have some method, I can understand the imposition of C&R only.

As for not catching from the still water you fish I can only recommend the approach we take. If the flies here reflect what you are fishing they are not the problem. What we do is find a likely spot and make the cast. Count the fly down as it sinks, so you know the depth. Then try different retrieves until you start getting takes. Then you will know the depth, and retrieve required. It is good to remember you can not retrieve line so fast that the trout can not catch your fly. The other day the retrieve that worked was to put the rod under your arm and use both hands to pull line in. A few days earlier in the same place they wanted the fly almost static.

What I would recommend is fly fishing for the species you know better. This will give you confidence in fly fishing. Catching something is the start to catching any species.

Yes I think it is an addiction, its been a long hard closed season here, and the lack of fishing has driven me to the local put and take (although they do permit C&R as well). I wouldn't be far out to describe the feeling as withdrawal. In the same way, in the season it can get to overdose levels. I must be a hopeless addict.

Hope that helps.

Cheers,
Alan.