What Gcalgske said!
But I'll give you my three pennyworth as well:
1) Apart from 'carb flu' (fortunately I only had a mild headache for the first couple of days, nothing else), should I expect any side effects?
Not everyone suffers from carb flu. Sounds like you're one of the lucky ones! No other side effects other than sometimes people experience a bit of constipation. But if you make sure you're getting plenty of fibre from vegetables and salad, as well as enough fat and plenty of water, you should be fine.
2) Apart from weight loss, what other health benefits can I expect?
Lots of Bootcampers report all kinds of other benefits! For me, it has sorted out my IBS and also never suffer from thrush these days. At one stage in my life I was getting this every month, for a period of two years!
In terms of the stuff I've read, a high carb diet is associated with tooth decay, obesity, diabetes, cancer and also Alzheimer's. Some are now calling Alzheimer's Type 3 diabetes. If you're interested, there are some really good books about the benefits - Gary Taube's book "the Diet Delusion" is a really good one (although it's a very weighty tome!)
3) Roughly what sort of weight loss can I expect? I lost 2lb in the first week - would this be about right?
You can expect to lose around 1-2lbs a week, but as you get nearer to your target, your weight loss will slow down. If you plot your weight on a graph, from start to finish, you'll be able to see the downward progression - even if the rate slows down.
4) I understand that I need to eat quite a lot of fat to keep me from feeling hungry, but am a bit concerned about cholesterol/clogged arteries. Will this become a problem if I eat LCHF long term?
A lot of what we're told about cholesterol these days is disputed - there's a really interesting book called "The Great Cholesterol Con", by Dr Malcolm Kendrick. Zoe Harcombe also writes some interesting stuff too. her blog is here It's actually better for women to have higher cholesterol.
However, actually you should find that LCHF (low carb high fat) eating sees a better balancing of your cholesterol levels.
It's also worth understanding that the evidence linking fat to coronary heart disease is very weak - despite what we've been told over the last 30 or so years. Again, read Gary Taubes on this, or "Escape the Diet Trap" by Dr John Briffa. Or Zoe Harcombe ...
5) Thinking ahead a bit, but when it comes to maintenance, what should I add back in to my diet? I was thinking along the lines of yes to whole fruit, nuts, higher carb veg (such as carrots and onions) and some legumes. I'm hoping to avoid adding anything sugary back in, so no cakes, biscuits, puddings, sweets. Also hoping to avoid refined starchy carbs (white bread, rice etc), but not sure about whole grains yet
Agree with GCalgske - it's a really good idea to follow the Atkins principle. Everyone has different levels of tolerance for carbs, so you need to work out what's going to work for you. Take it slowly, and introduce things gradually. I'd start by adding some carbier veg and/or some fruit. Then consider pulses/legumes.
Hope this helps! Look forward to 'seeing' you on Bootcamp!