Thanks all.
My breadmaker calls for 25g of butter, so I’ll substitute for about 23g of olive oil (which is what we have in the house).
This thread prompted me to try olive oil again in place of butter.
Recipe otherwise identical, 15g of fat in 440g of flour.
I felt the texture was tougher with oil and the keeping qualities less good. Not such a good rise (maybe the little salt in the butter affected?). Overall, I'm not convinced that the amount we're talking about (in a whole loaf) is going to have any influence on Cholesterol.