Please disregard my post above, that information WAS correct at one time.. but while looking for more information I came across this:
Letting fully furnished, part-furnished or unfurnished no longer has any implications regarding security of tenure for the tenant or for taxation.
So I'm sorry! next time I'll keep me gob shut until I make sure the facts are up to date!

I would suppose that when that was the case, it was a protection for people who would have to buy carpets and undertake decoration, etc.