Economy Mullard 3-3 stereo amp.

[Terry]

It seems it is based on the Mullard 3 - 3 design  ...

Yes, Mike - just one quick glance at that distinctive DC coupling arrangement between the EF86 and the EL84 is all it takes!

I remember once coming across a schematic for a Grundig add-on amplifier for converting mono devices with stereo capabilities to stereo and that arrangement literally jumped of the page! The EZ80 was replaced by Grundig's customary contact cooled bridge rectifier but apart from that it was a direct copy apart from one change: the 390pF capacitor in the tone control circuit became 400pF!