For me, the important questions are how would the choice of a male mammogram tech be communicated to the women attending for their mammograms, and would women who refused a male tech end up waiting longer for their mammograms - essentially being disadvantaged for their choice.
I do understand the arguments about male gynaecologists, nurses and midwives, but I appreciate the existence of a medical service that is aimed solely at women being staffed solely by women. I am not sure there is any particular benefit to women of having their mammogram done by a man, and would prefer the NHS to do more to recruit more women for the role, rather than just opening it up to men.
To be honest, I can see some men deciding to apply for this because they like the idea of manhandling women's boobs all day - not all of them, I'm sure, but if even a few slip through the net, that would be a bad thing.
A mammogram is not a pleasant experience anyway - do we really want to put in something else that would put some women off attending for their mammograms? Because like it or not, it would put some off. If I walked into the van and found a man there, I would not be happy - even if there was a chaperone.