I didn't want to put a downer on your lens Graham, its a great lens and a good choice, I just meant to say it would be something like a second choice for me.
I'm all for jumping in at the deep end so don't take any notice of doubts, I think whichever lens you have the learning curve will be the same or possibly accelerated with a wider lens. You just need to shoot some film and the results will come. If I can make one suggestion unrelated to lenses, buy a box of Fomapan 100 from AG Photographic and blast through it. It is lovely film, but 50 sheets cost less than 25 sheets of FP4, and if you are going to make any mistakes it isn't nearly so bad when you aren't counting the pennies!