The XK 140 SPC Publication J.15 of July 1955 lists only one wiper switch knob: C.4664 (Lucas 316.646). But Lucas catalog 400E refers to yet another wiper switch knob for the XK 140: 318.168. This might be a later knob for the XK 140 which could be replaced 1 : 1 for the early knob, meaning Jaguar did not change their part number.
I observe that early 140s have a wiper knob with a text lay-out, whereby the H N P start at "9 o’clock”. In 1956 we see a number of XK 140 instrument panels with knobs that I would call the “10 o’clock” lay-out. See pics below.
Are there XK 140 owners that can help in getting a better insight whether my assumption is correct? Does your XK 140 have one of these wiper knobs and what was the built date of your car?
Your help is much appreciated.