Hi Stuart, I like the sharpness of the body and lower wings and also like the interesting perch. Wish the top of the upper wing was sharp and I would consider cloning out the white blob above the right antennae. Overall a pleasing image. Including the shooting specs would help with image critique.
A very striking image, easy for me to say sitting here but I think presentation would have been better if it had been possible to take the image from a little further round to the left, this would have put the plane of focus more in line with the camera back.
Stuart,
Pretty sure this is actually a Queen butterfly and not a Monarch. There are 4 very similar butterflies: Viceroy, Queen, Monarch, and Soldier.
Queen is the only one with white dots in the middle of the hindwing, in fact this one is a male.
For a monarch the forewing will have black veins and the very tip has an orange island with black and white all around.