This looks like M. laui to me.
I have not seen before the plant being advertised as M. bocasana hybrid. If it is a hybrid, I wonder what it M. bocasana has been crossed with to look so alike to M. laui dasyacantha! It certainly has lost every characteristic of M. bocasana, the hooked spines, the radial spines, the flower colour, the woolly nature of the plant.
Do you think the advertiser has put the right picture into their advert?