Rods - as you know, I am a massive fan of Sonik rods, so if I were buying new, that's where I'd look first. I've never fished with the Sage/Hardy end of the spectrum, so not sure how much the extra cash buys you. I bought fly fishing outfits for my nephew and niece for Christmas, and I was really impressed with the little Shakey Sigma fly rods I bought them from John Norris - really lovely little 7ft 3 weights (originally ordered the 8' #4 but they were out of them). Only twenty odd quid, quite fancy one myself even though I've no need for it. Not quite the sort of thing you are looking for, but really puts value for money into context!
Lines - I also bought them John Norris own brand fly lines, and having had a swish about with them I thought they were outstanding value for money - £7.99!http://www.johnnorri...pro2-fly-lines/
My preference is for the Snowbee XS, I think they are the best lines I've used, but I thought the John Norris was closer to it than some lines which cost as much as the Snowbee.
Venues - catch and release - bit tricky, especially since you are looking for summer fishing. A lot of the smaller waters get pretty marginal for trout water temperature wise in the summer - they can become very difficult, and the survival rate of released fish is dubious. For that reason the place I used to fish, Churn Pool, stopped stocking trout in the summer and allowed coarse fishing. They've now stopped stocking trout full stop and are a dedicated carp fishery.
Bushyleaze/Lechlade seem to produce fish year round, but are catch and kill.
Manningford has a C&R lake, but I've never been there and it doesn't sound great from this review;http://www.flyfishin...-wiltshire.html
To be honest, it might be better seeking out some more varied river trout fishing?