  We explore the accretion geometry in Arakelian 120 using intensive UV and
X-ray monitoring from \textit{Swift}. The hard X-rays ($1-10$ keV) show large
amplitude, fast (few-day) variability, so we expect reverberation from the disc
to produce UV variability from the varying hard X-ray illumination. We model
the spectral energy distribution including an outer standard disc (optical), an
intermediate warm Comptonisation region (UV and soft X-ray) and a hot corona
(hard X-rays). Unlike the lower Eddington fraction AGN (NGC 4151 and NGC 5548
at $L/L_{Edd}\sim 0.02$ and $0.03$ respectively), the SED of Akn 120 ($L\sim
0.05L_{Edd}$) is dominated by the UV, restricting the impact of reverberating
hard X-rays by energetics alone. Illumination from a hard X-ray corona with
height $\sim10 R_g$ produces minimal UV variability. Increasing the coronal
scale height to $\sim 100 R_g$ improves the match to the observed amplitude of
UV variability as the disc subtends a larger solid angle, but results in too
much fast variability to match the UV data. The soft X-rays (connected to the
UV in the warm Comptonisation model) are more variable than the hard, but again
contain too much fast variability to match the observed smoother variability
seen in the UV. Results on lower Eddington fraction AGN have emphasised the
contribution from reverberation from larger scales (the broad line region), but
reverberation induces lags on similar timescales to the smoothing, producing a
larger delay than is compatible with the data. We conclude that the majority of
the UV variability is therefore intrinsic, connected to mass accretion rate
fluctuations in the warm Comptonisation region.
