Hi Sorcha
Another way you may be able to date your picture is by looking at the other pictures they all have a horse & rider over the entrance ways sitting atop of adorned block pedestal bases, yours has the horse & riders missing. Surley there's a waty to date those differences.
At first I thought I was sure it my home in a past life but then I realized I was reborn just yesterday.
Good Luck with dating this

BArry