There have been several postings about Hoary Footman over the last half month, not just on this website. I caught a possible candidate myself on the 18 June:
I've kept it, but I don't think it was a Hoary Footman as, when I looked at the hind wing
it was tinged slightly ochre in colour. So Scarce Footman, then. My back garden would have been a new site for Hoary F. I wonder if Scarce Footman often fades as it gets older.