Hayley,
I completely sympathise, you've had a terrible experience, and unfortunately with staffing shortages in most hospitals there will be an increasing number of women sharing your fears.
However, after spending a few days on a post-natal ward filled with c-section patients, I think anyone who would opt for that over a vaginal delivery needs their head examining.
It's not an easy option. Those women couldn't move for 12 hours, had to call for help just to pick up their babies or get a drink, they were sitting on soiled pads they were unable to change themselves, one spent the entire night vomiting uncontrolleably, catheters, IV drips, pain killers... Then you've got a long recovery period from serious abdominal surgery while looking after another child.
I'm not scaremongering. This is the reality of c-sections. (I'm sure someone will be on in a moment saying it's a breeze and they'd be more qualified than me to comment) but I felt like a complete fraud being up and about immediately.
You CAN have a positive second birth experience. I can strongly recommend the Gentle Birth Method by Gowri Motha and that you check out hypnobirthing or self-hypnosis. It can have a remarkable effect on your confidence that birth can be quick and the pain manageable. I was very worried about my 2nd birth, and this helped a lot (and I ENJOYED it, looking back!)
2nd births are generally faster and easier.
I'd also recommend you hire a doula or IM who can build your confidence beforehand and be with you through the birth...it can make a massive difference. Not least because you can stay away from the hospital for as long as possible.
But good luck with whatever you decide. In the end it's delivering a healthy baby that matters.