Diver300, that's a really nice offer, but I need the HV version
That's why I got really cheap ones, because the proper article is quite expensive. At least I've got 10 to have a go at. (Well, I did, 3 are in the bin now).
Dr Pepper, I'll try that with the resistor. I never thought of checking inductor current. Output voltage waveform is pretty messy though.
I bought two of the inductors so I'll try the other one. I went back and looked at the listing, they are sold as 5A ones so saturation shouldn't be the problem.
I attached a schematic and some photos. There's an extra cap in the photos, I thought extra de-coupling might help (it did a little bit)