A few more indications that the poet is describing Bath and not Stonehenge is the reference to 'red stone'. The way the minerals in the hot spring have coloured the conduits red is quite startling when you first see it. Also, the reference to mortar as in, ...rime on mortar. and, ...bound bravely the wallbase with iron, a wonder. Iron at Stonehenge? But iron at Bath certainly. What perhaps clinches it is the line, ...red arch twisteth tiles... I'm sure the Anglo-Saxons knew the difference between arches and lintels (their powers of description, for example, in the Battle of Maldon poem would put a modern war correspondent to shame) and this ...red arch twisteth tiles... is exactly what you an see at Bath today.