Red Mason bees!

Red Mason bees!

Observation - Red Mason bees! - UK and Ireland. Description: I am not sure if these are all male and female Red Mason bees, or whether there is another species i

I am not sure if these are all male and female Red Mason bees, or whether there is another species in there too. The first two photos show two different bees investigating the same hole which gives a good comparison of size. I'm still finding these very confusing!
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Edit following Steve Smailes' confirmation - thanks very much!