Pilot light woes

Hi All,

Wondering if I could get some ideas. I've got a Braemar WF2000 wall furnace. A few weeks ago the pilot light went out and when re-lit would not stay alight. I figured it was a faulty thermocouple so I went and got a new one. No difference. I tested the new thermocouple with a multimeter, works fine. The pilot light was a nice strong blue flame, but I thought what the hell I'll give it a clean. Disassembled it and gave it a good blow-out with compressed air. It was pretty clean anyway. Put it back together, still won't stay lit. The thermocouple is definitely in contact with a decent portion of the pilot light, and using the pilot light to test the thermocouple generated 20-25mV.

After this, I figured it must be a bad electromagnet in the main control valve, so I went and swapped it over (less than a year old and under warranty). Replaced that today and the damn pilot light still won't stay lit! I'm running out of ideas here, they're a pretty simple device and I've replaced the two most imporant bits. What else can I do?