You could have a look at Sarah Ravens' "Cutting Garden" book - not sure what the full title is. It will probably have suitable varieties, growing methods, timings and stuff. Her "Great Vegetable Plot" book is good, so the cut flower one should be too. She had a series of articles in "Country Living" magazine last year I think, giving planting pplans and varieties to give flowers for cutting almost all year.
Good luck with this.