  Layered van der Waals semimetallic $T_\mathrm{d}$-WTe$_{2}$, exhibiting
intriguing properties which include non-saturating extreme positive
magnetoresistance (MR) and tunable chiral anomaly, has emerged as model
topological type-II Weyl semimetal system. Here, $\sim$45 nm thick mechanically
exfoliated flakes of $T_\mathrm{d}$-WTe$_{2}$ are studied $via$ atomic force
microscopy, Raman spectroscopy, low-$T$/high-$\mu_{0}H$ magnetotransport
measurements and optical reflectivity. The contribution of anisotropy of the
Fermi liquid state to the origin of the large positive transverse
$\mathrm{MR}_\perp$ and the signature of chiral anomaly of the type-II Weyl
fermions are reported. The samples are found to be stable in air and no
oxidation or degradation of the electronic properties are observed. A
transverse $\mathrm{MR}_\perp$ $\sim$1200\,\% and an average carrier mobility
of $5000$\, cm$^{2}$V$^{-1}$s$^{-1}$ at $T=5\,\mathrm{K}$ for an applied
perpendicular field $\mu_{0}H_{\perp} = 7\,\mathrm{T}$ are established. The
system follows a Fermi liquid model for $T\leq50\,\mathrm{K}$ and the
anisotropy of the Fermi surface is concluded to be at the origin of the
observed positive MR. The anisotropy of the electronic behaviour is also
confirmed by optical reflectivity measurements. The relative orientation of the
crystal axes and of the applied electric and magnetic fields is proven to give
rise to the observed chiral anomaly in the in-plane magnetotransport.
