In this paper we study the tensor powers of standard representation quantum super-algebra $U_q(sl(2|1)$, focusing on rings its algebra endomorphisms, called centraliser algebras and denoted by $LG_n$. Their dimensions were conjectured I. Marin E. Wagner \cite{MW}. We prove conjecture, describing intertwiner spaces from a semi-simple decomposition as sets consisting certain paths in planar latti...