In reply to rossowen:
Specificity is key.
I set myself a sport grade target of F7a by this month (I started lead climbing at F5/6a at the beginning of the year) at the start of the year and although I've reached my target, I wouldn't say that I could consistently climb F7a.
The reason is (in my opinion) because my training has mostly involved bouldering in the week with route climbing on the weekends. I can boulder out a Font 6c/c+ crux, but get pumped in no time on a route.
So basically, by mainly bouldering I've made really good progress at bouldering, but my route climbing endurance has suffered. To improve at sport climbing, you should sport climb more (once a week is not enough to improve, as you've found out..).