I am another person who is terrible at recognising faces, and would recognise very few of my neighbours if I met them out and about. What really upsets ne us that my own mother doesn't understand it and thinks that it is a lack of interest on my part, but it isn't.
It is hugely embarrassing, and despite my many requests in the past to my husband NOT to bring people into our house (or anywhere else) and assume that i know who they are, he still does it sometimes. I am cringing now just thinking of some of the times this has happened.
Personally, I am more likely to recognise someone who other people might perhaps consider 'quirky' in some way that registers with me in a way that faces don't. When I say quirky, I just mean that there is something about them that stands out to me in a way that most people don't. It doesn't help me that so many women in particular have their hair cut, coloured and styled in a very similar way - men are slightly easier for me to recognise as they tend to be more natural, less 'cloned' than a lot of women.
I walk a lot, and there are people i can identify from afar by their posture and the way they walk, yet I would definitely not recognise them by face.
Similarly, I find voiceseasier to identify too, and am far more likely to recognise a voice on the phone, even if we have only spoken once before, than I am to recognise the same person if they were standing in front of me.
In fact, I once briefly encountered someone in Cheshire, on a canal boat, and six months later, this time in Worcester, I heard a voice in the distance and instantly knew it was the same person, but no way would I have recognised their face.