UKH

Can anyone tell me why the official advice is to keep washing our hands and not to touch our faces but there is no mention of actually washing faces?

No. I can't tell you. But I GUESS that when outside you might pick up loads of viruses with your hands when you touch things (door knobs, surfaces, anything); whereas you don't pick up loads of viruses with your face, as you don't touch things with your face (????)

That and once your face is contaminated I suspect you would need to be careful when washing as to not move it into your eyes. Washing hands is simple enough to do for the length of time which it needs soap to break down the virus whereas washing face I think could easily move it around into a more vulnerable area before it has time to work.