When I purchased my '98 XJ8L a couple years ago she had "green" coolant, which was subsequently flushed and replaced with orange JLM20972* coolant.
A) Is the orange coolant the correct coolant type for my vehicle? I trust the Jag mechanic I go to, but I'd like to make sure.
B) If I wanted to fill coolant myself, would any orange long-life coolant/antifreeze suffice or would Jagaur "brand" coolant be required?

Thanks

 

Edit: disregard this edit.

 

The colour of the coolant does not tell anything about the type/chemistry of the coolant. What is important it not to mix Glycol based coolants with the fairly new OAT (Organic Acid Technology) coolants. If it says "Glycol" (Ethylene Glycol) on the JLM20972 coolant you used, there is no problem mixing it with the traditional green coolant.

Otherwise, the traditional "green" coolants also come in blue, red, orange and what not colours. On the other hand, the "danger!" OAT coolants also come in colours other than orange - typically in amber, dark green and red but could come in other colours as well. So, don't go by colour but make sure you mix Glycol with Glycol and OAT with OAT (if OAT is what your engine has from the beginning). The colouration is there just to make the coolant look "pretty" and also so that you can choose its colour which is different from the colours of your engine oil, transmission, PS and brake fluids, so that you can easily recognise which one is leaking.