Thanks for the reply!
The engine is super-charged and this sensor is located after the intercooler and before the inlet manifolds it is marked solely as 'AT', so I am guessing it is the ACT. I have not located another air sensor despite repeatedly looking!
Is there a chance anything untoward may happen if I do reconnect it? Am an interested to see if this will help solve the laboured cold starting I am experiencing.
I am also seeing if I can access the Map, although pushing my knowledge here!