These are the Capacitors I have tried in the Phono Stage output and a brief description of their performance.
From top left and working clockwise:

WIMA MKP 10: Detailed and dynamic, let down only slightly by soft and sibilant treble. Analytical, lacks Musicality.

ClarityCap ESA: Warm and musical with emphasis on mid bass and midrange great for drums. Slightly sibilant.
Russian PETP: Musical and fairly well balanced, top end is slightly emphasised, bit superficial overall.
Sonicap Gen1: Very detailed crisp and clean mid/top too laid back at the lower end, lacks dynamics there.

The WIMA's and ESA's both improve at the top end if bypassed with a 0.01uF Vishay MKP1837 capacitor, but there is something still not quite right about the presentation. The search continues!