Heating Water Circulation Pump & Coolant temperature errors

[Riva811]

Hi I recently had my radiator replaced after it cracked by MB Brentford (who did a sloppy job for lots of money). I got the car back obviously but my diagnostic is complaining for a couple of things:

1. Component M13 Heating Water Circulation Pump has an open circuit or overload
2. From time to time If i push the car during cold winter the oil temperature will fail to go above 70C and the check engine light goes on. Switching the car off and on the car shows the right temperature 90C and then error moves to historical.

I joked in the past that I will replace the coolant pump with a racing one, did the time arrive? Also, is the 2nd error a thermostat error?
Anyone aware of a good indie in west/southwest zones 2-3 that can look into it? As I lost all faith to MB aftercare. Aware of Klasse in Fulham but I didnt hear much about them

 

[Riva811]

If this helps out anyone in the future, the errors occur when the coolant is very low.