having a quick google,there is no fantastically detailed picture of Speke hall,but one I did find seems to show the little inset area on the bridge in which they appear to be sitting.
Coincidently I have had a reply on GC from a query I made regarding PURT surname,one of my grans sisters married name. She says initially that the Purts she has in the tree are from St Helens area. I wont get my hopes up but does sound promising.