A Hyundai i10 sounds perfect. Not only will you be used to how it drives, but it's also a very reliable little car that'll be cheap to run. We'd also recommend the (very similar) Kia Picanto, while it might also be worth considering slightly bigger cars like the Ford Fiesta. In terms of finding a trustworthy second-hand dealership, it's a bit like anything these days – look at reviews and go with your gut instinct! Most reputable dealerships will have reviews on Google and Auto Trader, so check them out, and speak to people you know about local dealerships. If the sales people are too pushy or something doesn't feel right, walk away. It's worth looking for things like AA or RAC dealer accreditation, too.