This paper shows that the Liverpool English dorsal fricative, derived through the lenition of /k/, is subject to place of articulation assimilation, driven by the preceding vowel. This is similar to the vowel-driven aspects of typical perseverative Dorsal Fricative Assimilation (a type of palatalisation), as found, for example, in the German ich-Laut~ach-Laut alternation, where (among other things) a preceding front high or mid vowel is followed by the front dorsal ç, and other vowels are followed by a back dorsal. However, the majority Liverpool English pattern differs from previously described cases of Dorsal Fricative Assimilation in that ç only occurs following long front high vowels, while a back dorsal remains after their short congeners. This type of quantity-sensitive pattern in assimilation has not been reported before. We use Centre of Gravity measurements to investigate this pattern of place assimilation, and argue for the use of an innovative normalisation technique for consonant measurements, based on measurements of /k/ aspiration in a linear regression model. We thus both expand the taxonomy of what is known to be possible in phonology and also provide new detail in the description of Liverpool English (including a proposal for the featural analysis of its vowel system).