Hi Andrew. A bit difficult as though they look to be outside, this is no guarantee that they are a hardy plant. There are quite a few plants with this form from various different families, hence the difficulty in id'ing them. Could be a type of Draceana but probably more likely to be a member of the genus Carex though the base to the leaves looks thicker than most I am familiar with.

This may sound a bit silly, but they may be artificial to look so perfect esp at this time of year.

You could well be right. It did cross my mind also :-)

Assuming real, could they be a Stipa? Maybe in containers planted and changed on a regular basis by one of those companies that provide plants to hotels and other commercial premises.