I always feel (rightly or wrongly) that you will pay more going through an agent, so I always tend to book direct.
For the past three years, my wife and I have been visiting here and were off again next Saturday. We were supposed to be going today for two weeks but unfortunately a family bereavement sees us delaying for a week.
http://www.theretreatlake.com/
My wife doesn't fish, although she will come and sit with me in the evenings and read a book or act as my net fairy if I happen to hook in to anything decent.
We rent the Gite (sleeps four comfortably) and it costs £950.00 for the week with exclusive use of the lake. The owner (Lyn Holland) may do you a deal if you are prepared to book for two weeks, but I can't guarantee it.
The place is absolutely gorgeous, miles from anywhere, and the lake is pristine (as is the accommodation!). You're not going to catch a true monster, but the fish go up to mid 40's and whilst not a runs water, it's not too difficult. I had a 33lb Mirror out twice last year, and a large number of high 20's. My daughters boyfriend also had a 31lb Common out in beautiful condition.
You are about 15 minutes drive from a large town (Chateau Gontier) with a very large supermarket, restaurants, bars and enough shops to keep the ladies occupied!
I generally fish from 1st light up until about 10am and then spend the day either shopping, eating or just lounging about with the wife in the immaculate gardens. Two brick built barbecues make life very easy, one of them is actually in my favourite swim so you can spark up and eat whilst fishing! I then start fishing again from about 7pm until darkness. My daughter and her boyfriend fished a couple of nights while we were down there last year, but didn't catch so I don't bother. Don't want to be seen to be too selfish as far as the wife is concerned!
It's about a 4.5 hour jaunt down from Calais, but don't let that deter you. It's worth the drive. The roads in France are much (much) better than over here, hardly any holdups and the drivers are sensible. It would take me longer to get to the Lake District from here so I don't mind the drive at all.
Highly recommended.