  We present an analysis of the results of long-term multi-band photometric
monitoring of the enigmatic star, KIC 8462852. Observations in the $B$, $g'$,
$V$, $r'$ and $I_C$ passbands have been acquired at University College London
Observatory (UCLO) between May 2017 and September 2018. We interrogate the
wavelength dependence of the $\sim$month-long dimming and brightening exhibited
by the target star over an 85-day interval, immediately following a days-long
$\sim5$ per cent drop in brightness on Julian Date (JD) 2458203. Between JD
2458215--300 we measure brightness variations which correspond to relative
extinctions of $A_B/A_V = 1.39\pm0.27$, $A_{g'}/A_V = 1.16\pm0.11$, $A_{r'}/A_V
= 0.80\pm0.25$ and $A_{Ic}/A_V = 0.49\pm0.19$, from which we infer an
Angstr\"om absorption coefficient of $1.33\pm0.43$ ($R_V \simeq
3.2^{+2.6}_{-1.0}$). As with the days-long `dips', the wavelength dependence of
the longer-term brightness variations must also be associated with extinction
arising from a dust distribution containing a substantial fraction of
sub-micron-sized grains. This implies some common mechanism is responsible for
the star's variability over both these short and longer timescales.
