The Glastonbury Zodiac is multi-layered. There are the Zodiac effigies themselves which are the shapes of the zodiac creatures formed by the contours of both natural and man made features in the landscape (road, field boundaries, rivers etc...).

There is also the planisphere (star chart) layer. To verify the existence of a landscape zodiac, one must be able to place a planisphere (star chart) over top of the Landscape Zodiac in such a way that all of the stars in the planisphere align with correlated features in the landscape. Katherine Maltwood, the women that is credited with discovering the Glastonbury Zodiac goes into great detail about where all of the stars 'fall' in her book A guide to Glastonbury's Temple of the Stars.

To my knowledge, Katherine does not speak specifically about the location of the Milky Way but if you know which constellations are located along the Milky Way, you can figure out where the Milky Ways is in the Glastonbury Zodiac.

The Milky Way basically starts near the front paw of the Leo effigy, runs north along the top (East) of the Gemini twins, cross the nose and head of the Taurus effigy where it curves east thru the waist and along the back of Sagittarius passing finally thru the tails of both Sagittarius and Scorpio.

Katherine's guide plus other information and images of the Glastonbury, Kingston and Victoria Landscape Zodiacs can be viewed at the following link.