Thanks for that. I had a look at refractometers and test kits etc but none of them can tell me what type of antifreeze I have, just the concentration levels.
Nevertheless I used my identical refractometer to measure the unknown OE coolant in my car and the fresh Mannol, and both indicated exactly -40°C freezing point (can't remember which scale I used). For that reason I didn't dilute the Mannol which was the recommendation anyway. Anyone diluting the same 50/50 would be well advised to check the freezing point afterwards unless using concentrated coolant with specific dilution and performance recommendations.
BTW this device showed that my Land Rover coolant had dropped to just -10°C protection due to frequent topping up with water needing me to add undiluted fresh coolant to increase protection.
