Hey, if you're a total novice starting out, I cannot recommend strongly enough that you join a local club where more experienced members can give you advice once they see how you progress but to answer your questions:
1. You could probably have enough to "get in and go" with 10-15 hours' tuition. Once you have the basics of paddling forwards, backwards, turning, eddies, edging, draw strokes and swimming you could probably go out (with people) and do some simple stuff. Joining a club will take care of this
2. There are no "requirements" - no one will stop and ask you for a qualification on a river as this tends to be an activity we do in the middle of nowhere, far away from help. With this in mind, it's very useful if at least one person in your group has a working knowledge of first aid. A safety and rescue course like FSRT (Foundation Safety and Rescue Training) is the first step, followed by the WWSR (White Water Safety and Rescue) in rescue qualifications but these take second place to getting your own paddling skills up to scratch with a BCU star course in order to try and avoid needing WWSR knowledge in the first place. Again, going on a trip with a club means that there will be people who have this experience already.
3. If you join a club, you don't need to buy kit for a long time - basically until you decide for yourself exactly what you want as you can borrow almost everything. To run the mad stuff, you will need a big volume boat like the
Pyranha Burn or
Zet Raptor or something of that ilk but boats are expensive (£700+ usually). To be frankly honest though, it will likely take a while before you are ready to do grade 5 rivers like the
Braan and your tastes might change by then so for a first boat I'd get something second hand (remember how I mentioned joining a club? There are often people selling kit on as they upgrade/move country/etc...)
4. Before you even think about getting a kayak, you need a decent paddle, life jacket is crucial to not drowning(we call them Buoyancy Aids or BA's on account of a small technical difference) and most importantly a cag (waterproof jacket) or drysuit to keep you warm and dry. Literally, the most important thing about going out on the water is being able to stay warm, comfortable and usually dry. There are few things worse in life than being cold, wet and sore on a river
. A decent BA will set you back £40-£100. Cags are about £80-£150 (
Lomo make a very good drycag for £100 which represents a similar price/performance ratio as the HD5850 did way back then
). Drysuits are double the price. You can also get a wetsuit for significantly less (£30-£100) as I did and eventually upgrade if you decide to stick with kayaking. I forgot to add a helmet to stop you getting brain damage; £25-£60
Moral of the story - join a club. Here's one that seems to be local -
http://www.eycc.org/
Welcome, you're in for an amazing sport/hobby/life-stealer