[glyphmon]

In response to MrFixr55's tube-pulling suggestion, here's what I've done so far:

With the 6A8 removed, the 6K7 shows 138.7V on pin 4, as opposed to the 63.5 previously measured and compared to the expected 100.
With the 6K7 removed, the 6A8 shows 107.2V on pin 4, as opposed to the 63.5 previously measured and compared to the expected 100.
With both 6A8 and 6K7 removed, the voltage on the tube-side of C15 and R4 is 218.

The first result seems to be as not good as originally tested, though in the opposite way.  The second result seems reasonably close to expected, well-within 20%, but then again, I'm not yet sure how these interact and affect voltages.  The reading with both tubes removed is almost twice what is shown on the 6A8 with the 6K7 removed which, if the 6A8 is acting correct, may be expected?

Do we need to check deeper or is there something apparent at this juncture?  To my untrained eye, does this suggest that flow is going too easily (maybe not quite a short) through the 6K7 and it's cannibalizing the current?

Best wishes,
Roy