The Avenue

I caught this vision a few days ago, out of the corner of my eye, driving through. The Avenue, Bridge of Allan. 
It has its own sign, and a bloody marvellous arched entrance. Now, it is a 10 yard sprint through Stirling Council wheelie bins, left oot the back.
I wonder what it was when the stonework was built?
One of the many reasons I love Bridge of Allan. Posh, but not posh. :-)