Barbara I can’t recommend for narrow feet (mine aren’t!) but I can highly recommend Cotswold Outdoors as a place to find a pair that fits well. They measure your feet flat and on a slope (I hadn’t had my feet measured as an adult), and look at your foot shape, and work from there.
They fitted me with two pairs that were comfy, explained the pros and cons of each (light but less suitable for very rocky ground versus heavy but would last longer with heavier use), and told me to check prices on the internet and they would match them. Fantastic service!