Lots of good questions here.
1. as far as i know, solicitors tend to get paid more in the beginning of their career than barristers, but barristers earn more further down the line: is this true?
The question of pay depends substantially on your area of practice. For example in crime, the average solicitor and the average barrister will probably be earning roughly the same throughout their careers. However with commercial work for example, junior solicitors and junior barristers may earn roughly the same (with solicitors perhaps earning a little more in their very early years, although don't forget pupillage awards are tax free and salaries are not). But then the earning potential for a top notch commercial senior junior or silk is likely to be a lot more than that of a senior associate or partner at a commercially-focussed firm. So the rule you describe probably holds truer on the commercial side than the criminal side. Having said that, some of the really outstanding criminal silks will earn millions, which is more than any partner at any criminal solicitors' firm in the country.
2. i would love to be a barrister, as i've heard many find it more intellectually stimulating and you have more free will, but a) i'm not very good at public speaking, so how would you recommend i improve (?) and b) does the independence make it a more 'risky' career than a solicitor (not guaranteed to get work etc).
Great that you're considering a career at the bar. There are some barristers who do far more public speaking than others. Some commercial barristers have a largely paper-based practice, and will rarely go to court. Others (family, crime) will be in court almost daily. So if your preference is for less advocacy, there are ways of achieving that. However, three very important caveats. First, advocacy is a key part of being a barrister; it is the main skill that marks you out from solicitors. Second, it only gets better with practice, so to some extent you have to just grasp the nettle (and you might find you enjoy it more once you get over the initial fear). Third, you are really going to struggle to get your foot in the door in the first place unless you can demonstrate experience, and a basic level of competence, in advocacy. I suggest you try some low-risk public speaking exercises (school / university debating club, mooting etc) to dip your toe in the water. If you truly hate it, then you may need to reconsider the bar. On the second part of your question, yes it is certainly a riskier career, both in terms of chances of getting in in the first place, and then being self-employed afterwards. But that's part of the trade off for the benefits you describe.
3. in regards to being a criminal barrister, i recently began reading 'stories of the law and how it's broken', where the barrister writing talks quite a bit about how disorganised criminal courts are, and how stressful their job was, sometimes getting cases 20 minutes before they had to present their arguments: would you say that this is your experience too?
In short, yes it is. There is plenty of chaos, last minute case prep, missing material etc. But for me, that is part of the fun. It's also not always like that. Cases in the Magistrates' Court are generally much worse for that sort of thing (e.g. if you are prosecuting a list, you will be in court all day as the prosecution advocate on anything up to 15 or so different cases, and you might only get the papers through the afternoon before, and half the stuff you need is missing). But in a bigger Crown Court trial, things will generally be much more organised. It's largely a product of the seriousness of the crime involved, and therefore how much police and CPS attention gets paid to it.
4. sorry, final question, but what would you say your second favourite area of law is and why?
For me personally, public law. I love crime, and the jury advocacy that goes with it, but I'm also quite a techy lawyer and I like a good bit of legal argument. There's more opportunities to do that if you can supplement your criminal practice with a bit of High Court public law work, and there's often a crossover with crime anyway.