In that case, I would say that c. 1.5m might be more the target here?
I honestly have no idea.
It looks good from the outside; there are no dimensions on the floor plans or in the listing text, but the layout looks OK with no big echoey spaces. So it's not a white elephant.
OTOH for many Dubs Naas may as well be the dark side of the moon, and even in Kildare terms it's the wrong side of the N7, and (as you've observed repeatedly) non-period structures depreciate.
edit: I did try to buy something a similar distance out (and similarly rural) in Meath a while back, that I valued (generously) at 15k/acre + current build cost, but the vendor wanted 30% more than my valuation so I bought something else instead. There does seem to be a bit clinging on to noughties valuations, either due to not wanting to realise paper losses or due to some fantasy that a property developer is going to come along and build an estate in the middle of nowhere.
Horses are fun but expensive and/or time consuming to keep. The rental yield on grazing land is ridiculously low, but I suppose in EA terms that means the opportunity cost of keeping them is also low!