Thanks all,
As Cerrem said. For comparison purposes many OPTs state primary inductance at 5V 50 Hz (or perhaps 60 Hz where applicable). Not to go into the whole theory again; I use this value to start, but also other exitations to check NFB stability. Cerrem gave a lot of detail in the earlier (quoted) thread.
I found 35 Hy at 5V 50Hz plus some 30 mHy at 1 KHz. Yes, somewhat mediocre, rather high leakage for all of 6 secondaries, but satisfied Sir Peter's demands. Further detail for rewind: Original laminations were cut to a different standard than lossless, more winding window area. It can be such a mess to retrieve the original core that in the past I decided to go for new, at approximate similar specs. I do not feel that will be cheating collectors when original 'originals' are not available any more.
Anyway, all said before. My thanks for members' reaction. Still a personal laugh in the mirror for having been unable to relocate my own posts!
P.S: Nominal loading is achieved by the low values of R10, R11.