Even though it may be a hybrid, you should name it as walkeriana until you have proof otherwise. The leaves look a bit like pendentive which has loddigesii or dolosa in it....so they say. It could very well have some pendentive and/or dolosa somewhere in the background.
I have crossed pendentive with coerulea in an attempt to get full blues however both white and blue genes are recessive so god knows what will come out. (they should flower within 18 months)
Anyway, I made sure to clearly label the parentage! This line has leaves like your plant. Some single, some bifoliate, thick roots etc......
Oz, how do you open up the orchid digest articles on that link?