Hi there,
My friend and I (both of us female) went to England and Scotland a while ago. We stuck to public transportation and I thought it was great. The buses are clean and on-time and trains are wonderful, if a little more expensive. Neither of us even thought about renting a car and we really didn’t need one. A bus or train went to just about everywhere we wanted to go. And if there wasn’t one, well, walking is good exercise!
In the US cars are just necessary. I hate them, but I need them. In the UK though, there is a lot more public transportation and I really think that is the way to go. And the couple times I got lost, everyone I talked to was very friendly and willing to help. I once even had an older woman get off with me and walk me to my hostel, and it wasn’t even her stop.
I am going to the UK alone this summer as well. Thankfully I have a friend that I will be staying with in Leicester. I am debating on how I am going to travel around myself. My thought is to get a rail pass and do it that way. I am a male however and it is a little easier for me to travel alone. I am with you on not feeling comfortable with renting a car.