Quite right, Peter. My XK120 used to blow fuses on a left turn, and I traced it to the manette wiring. Where the stator tube inserts into the manette, there is a sharp edge, and it had worn through from decades of pulling the wheel in and out, and the left signal wire was grounding.
Here is my '38 manette.
Some one on the XK forum named Dave has some unknown manettes, you might try him.