I found a pair of cheap PP-transformers and found these very suitable for a EL84 amplifier. First I had planned to go for the design found in Morgan Jones "Valve Amplifiers" but was adviced to avoid that very construction. Instead Lasse Ohlsson (ElektroAkustic & Music) proposed a different solution.
I have almost manage to complete the amplifier apart from some "loose wires" from the PSU to the amp boards. Maybe I should mention that at the moment I have been using the amplifier as a sparepart supply. I just have to make a few ground- and HV-connections and I noticed that a tag is loose on one transformer.