Origin of the name 'Mow Cop'

According to Wikipedia, the name is first recorded as "Mowel" around 1270 AD.  Two possbile origins are suggested:

1. the Anglo-Saxon 'Mūga-hyll', meaning "heap-hill"; together with the word 'copp', meaning "head", added later,    OR
2. the word 'moel', meaning "hill", from the Common Celtic ancestor of the Cymric/Welsh language, together with the Anglo-Saxon word 'copp' added later.

The 'heap' part of the name in option 1 above is thought to refer to a cairn which even in those far-off days marked a boundary point!