Ha! Fly fronted trouser, I scoff at you!
I have just completed my first fly fronted flare (try saying that after a couple of glasses of Rioja) and am feeling really quite clever!
I used a 70s McCalls pattern which came from a car boot fair without instructions. Out came my trusty friend the Readers Digest Complete Guide to Sewing, and together, we worked out how to add "some" inches to the waist (Eek, did a size 12 really have a 25" waist in the 70s? Who was eating all those Vienetta's?) and how to fashion a pretty decent fly.
Whoop whoop, I'm so pleased I did a little victory dance in the garden...