For anyone thinking about trying this.
TF1 isn't free-to-air (FTA) on 19.2E, it's only FTA on 13E. If you can pick-up both 19.2E and 28.2E (which is where your friendly Sky Installer points your dish when it's setup) at the same on a Sky Mini-Dish you are doing very well. You'll never pick up 13E and 28.2E at the same time with one LNB block.
I've just setup my system, initially I tried two separate LNBs on a 68cm dish, results were a bit hit and miss, whilst I could get a separate sat feed to each LNB I couldn't get the two satelites I wanted. I'm sure with time I could have got there, but I was fed up with standing on a ladder messing around with the angles.
What I have ended up doing is buying a motor to drive the dish to the approprate satelite, much easier to setup, you just have to point it at one satelite, from that it can work out where the others are (there's a bit more to it than that, such as finding south to get the right angle to track the arc of satellites). Most Sat-Tuners have built in software to power the motor and drive it the appropriate location, motor was £50 and could be fitted to any dish.