The turn signal switch has not worked properly for more than a few weeks since the Sunbeam rolled off the truck in 2016. 
When the car arrived, the turn signal stalk drooped down and was permanently signaling a left turn. It turns out that this is a common problem with Sunbeams that caused by a broken plastic part in the switch mechanism. Repair kits are available, and I tried twice to rebuild the switch. To the right, the green arrow points to the white plastic piece that holds the switch stalk in place. I was unable to adjust the cancel pawl (red arrow) so that the signal turns off after a turn. Either the signal did not turn off or the pawl became stuck on the white plastic part. I did not want to drive around town with the blinker permanently signaling a left turn. I am old but not that old.
I gave up on the Sunbeam design and 
moved on to a switch for the Triumph TR6. I had read in the Sunbeam forum that this was possible; the TR6 part was made of metal, and I thought it might be better. The picture on the right shows the Triumph part jury-rigged onto the Sunbeam steering wheel column. Because the steering columns in Sunbeams and Triumphs are different and the stock mounting bracket would not work, I needed to improvise. I used two halves of a radiator hose clamp to hold the TR6 switch in place. The ends are attached to top and bottom of the switch using 4mm screws and then tightened onto the steering column using the worm gear on the radiator clamp. You can barely see the worm gear on the right side of the column.
My first try with the TR6 part proved the concept but was not successful–the signals worked but the auto cancel feature 
after a turn did not. A second attempt showed I was on the right path, but was not quite there. The second repair lasted only a few weeks, and then the left turn cancel stopped working. It turned out that I needed to move the signal cancel cams (red arrows) closer to the pawl mounted on the back of the steering wheel.
To move the cams, I shifted the entire switch. I decided to drill and tap new mounting screw holes on the turn signal body so that the radiator clamp would remain in full contact with the steering column. In the last picture, you can see the old mounting holed (yellow arrow).
Will it work? I have driven the Sunbeam twice for a total of 20 miles, and so far so good. The signal switch turns on the indicator lights and the cancel function works in both directions. Just in case, and so as not to tempt fate, I have not put back the trim covers…
Sunbeam 