Chris really glad you posted the pic. as I had a look at the link you gave and everything fell into place
I know now that Mount Street recreation ground was once the site of the old mill pool, (Map Following) the mill was called Park Mill fed by the River Rea it made Harpoons, Machetes,Spades, Shovels, Hoes,and all kinds of edge tools when the pool was filled in in the 1900's the mound or "kop"was left
I have two photo's of the Mill and pool just been sent to me by e-mail (copyrighted) and will send them if you are intrested as well a a great drawing of the mill