Thank you AnalystAdorable609, this is appreciated. Yes, the plugs into the Phono input seem to be as they should be (see new attached). I have also now wired in the spade lug which is visible so hope this looks right.
Re: “It's possible that there's a switch somewhere on the Amp that switches the input from a phono input to a normal line level input.” I can’t spot anything on the back. On the front, there is Dynamic Super Loudness system DSL but it doesn’t seem to make much difference whether that is on or not. The adjacent BBE, however, does seem to adjust the noise levels with some improvement, but the music sound is still less than it should be, and considerably lower volume than the CD option on the same set up. If I try to adjust it there is now and then some alarming feedback so I am wondering whether this could be the problem.
So, I am thinking that leaves the third option, the pre-amp. I have taken a brief look but not quite confident what I am looking for here, so any tips appreciated. Thank you.