Face coverings for blood donors

In discussing the current pandemic, the NHS blood donation website says, We are advising donors to wear a face covering when they give blood. However, yesterday evening when I went to donate, they were quite clear about having us all take our masks off on entry, also our gloves. It was a relief to note that the room we all shared was ventilated with fresh air. I wonder if donor masking is yet another policy difference between England and Scotland.