Hi TolkeinTeddy
I'm a PhD student in lit, nearing the end of my research now.
In my experience a 2:1 on your BA shouldn't be a deal-breaker at all - I've known several really great research students without first class undergraduate degrees. If you've done well with the research component of your BA and produce a solid MA dissertation that should be enough to convince institutions that you've got what it takes to tackle a research project in your field.
It's possible that funding will be slightly harder to come by in theory as panels look to distinguish between large numbers of worthy applicants. That said, I can't imagine any funding body would ignore a strong, well-supported, doctoral proposal purely on the basis of an undergraduate degree.
As for the writing, well, that's one of the things studying a PhD will help you develop. At my institution we actually have a first year doctoral "module" on academic writing.
If you're keen and you've enjoyed your MA, my advice would be to go for it!