Up where you are Bryan perhaps not -but if you are travelling through Auckland very much an advantage, as I learnt sitting in the carpark at Mog 18 you can tell a plus eight approaching without looking up as their fan is running hard.
Not all +8`s have their fans running for much of the time. I think it may be possible that when EFI lean burn fueling fueling was introduced to better suit emission reg requirements that there was more dependance on cooling fans than there is in my mid 80`s carb fed +8.
I remember running in Front of Spanner Juggler in his then new +8 ( Circa 2002) on a Lakeland tour, when passing through town and stoped at either junctions or traffic lights, that his fan seemed to be constantly running.
I also suspect many a Morgan may be fan dependant as the result of crud build up in the cooling system, lack of regular use can cause crud build up. Add to that the possibility of tuning mods where cooling might have not been considerd relative to the extra heat generated ..etc. etc..?