They didnt actually celebrate the new year after the Winter Solstice, but after the Harvest (Around the beginning of November)
Well said Caldrail but my comment was but intended to convey the possibility that the Stonehenge was not designed and built as an astronomical observatory (certainly unrelated to stars which were too minor as objects, but as regards to sun/moon/earth cycles instead), and that other possibilities ought to be considered. My comments were inclined to agree with Longshotgene in that regard.
Consider: a distant tree line 100 feet high and 1.1 mile away would delay a sunrise by 4 minutes, a half mile by 8 minutes, and a quarter mile for 16 minutes. Were the forests cleared in all directions, round-about or at least easterly and westerly for a mile, a half mile, or a quarter mile?
An observer with a desire to see a sunset might feel inclined to seek higher ground to be sure of seeing the actual sunrise rather than one delayed by obstacles like trees or even small rises in the terrain. A builder desiring to commemorate special sunrises and sunsets might consider a higher elevation if it would yield a