Blocking Radiator ???

[DesertMK4]

Is there some confusion here? Many Cobra gauges, in order to be more "classic" are set up in Centigrade. So 100C=212F. A 70C engine temp is a little low, but not as an opening point for a thermostat. A 70C oil temp is also a little low assuming you have fully warmed up and the ambient temp is above 35C. A sandwich thermostat on the oil cooler can help here. Raising the engine thermostat rating will tend to raise the opening temp, and tend to keep the engine temp higher overall. Using the thermostat to set a specific point in operating temp is a lot of bother when the range of cold (70C) to very hot (110C) is 40C.
Gauge watching is one reason most production temps are centered weighted at the mid point of the "good range" for the car. The motion may also be damped at the center (as BMW does).
If you are racing it makes a big difference. If you commute a lot, oil temp can make a big difference in avoiding cold oil sludge problems.
Otherwise...relax and drive like you stole it.