411 S3 temperature gauge sender

[Green411]

Hi David/all
I keep everything, which of course means I can never find anything! That includes the original tamp switch, which I only took of a month ago.....d'oh....
I found part number 911-1-35052 on an invoice in the history file for my car & used for a replacement temp switch. But there's no guarantee that's the right number (although it was Bristol who fitted it so I hope it was right!) & searching on that number brings up nothing useful.
Have also tried to plot a resistence curve, with limited success:
80*c = 87 Ohms
77*c = 91 ohms
75*c = 100 ohms
70*c = 121 ohms
60*c = 165 ohms
50*c = 250 ohms
The temp gauge always seemed read a bit high - just above halfway, between 90 & 100 at normal open road speeds. About 3/4 of the way up the gauge when the fans came on (98/93* switch in top rad tank)
Cheers
Mark