That's a nice plant, Peter.
You certainly had to have a lot of patience - 17 years - to finally see this cactus in bloom. Is this your oldest plant?
Also, image two shows what looks like perhaps a Peniocereus greggii. Do you have flowering size plants of these?
If I am really lucky, one of my plants may actually produce a blossom or two later this year. However, I do not see any definite sign of flower buds.