OMG, I am the stupidest person in the world. I had accidentally swapped a rectifier and a output tube. Flipped them and all is good. Hum sound that started this whole thing is gone.
When doing the soldiering I was so careful to get the wires back in the right place, checking and rechecking my job against the photos I'd taken. I came in the house and popped the tubes in the wrong sockets and whammo. Nothing.
Alls well that ends well!
>>Thank you so much for your help. I apologise for my dumbness<<<