Which Warning Light ? We have an answer!!

[Stuart McB]

And the winner gets a prize of ... [?]
If you had to put a litre of water in no wonder you had a disco going on [:D]
Seriously, if you think you have a fault do a search on this forum under "expansion tank" or "radiator" as this will put your mind at ease.

[NiSk]

You're lucky it wasn't an early BX - when any of the fault conditions occur (overtemp, low level, oil pressure, etc, etc) on one of them, the whole lot light up! (including the BIG RED STOP lamp).
Great fun trying to fathom out which sensor is responsible!
//NiSk