Girdle of Lepidochitona cinerea has a unique (in N.W. Europe) lozenge pattern, its elements are:
Alternating dark and light transverse lozenge-like bands of approximately equal size.
1: narrow waist of dark band interlocking with bulging waist of pale band (sometimes colours interchanged).
2: central dark spot on pale band, and white spot somewhere on dark band (in this case, near margin).
3: pale grey (or whitish or pale brown) longitudinal line often runs across, or near to, the waists of bands.
But sometimes markings are indistinct, especially on whitish specimens which are easily confused with Leptochiton cancellatus see image a 14 Leptochiton cancellatus album COMPARISON Lepidochitona cinerea .

KEY ID FEATURES and similar species at: 02 Leptochiton cancellatus