Hi,
the tube restainers are made of metal wire, and i bent them myself to look like the el84 retainers, but it's was difficult to miniaturize it...
I have some gut shots, but they ain't pretty. I tried to follow a PTP design, and soldered the tubes direct to the board, the retainers maintain the tubes in position.

on this one is possible to see that the SMPS is based on max1771 and is mounted on the baffle, between the speakers, and above the output transformer.

Thomas