Context : Our consortium performed an extensive multi-wavelength campaign of the nearby Seyfert 1 galaxy NGC 5548 in 2013-14 .
The source appeared unusually heavily absorbed in the soft X-rays , and signatures of outflowing absorption were also present in the UV .
He-like triplets of neon , oxygen and nitrogen , and radiative recombination continuum ( RRC ) features were found to dominate the soft X-ray spectrum due to the low continuum flux .

Aims : Here we focus on characterising these narrow emission features using data obtained from the XMM-Newton RGS ( 770 ks stacked spectrum ) .

Methods : We use SPEX for our initial analysis of these features .
Self-consistent photoionisation models from Cloudy are then compared with the data to characterise the physical conditions of the emitting region .

Results : Outflow velocity discrepancies within the O VII triplet lines can be explained if the X-ray narrow-line region ( NLR ) in NGC 5548 is absorbed by at least one of the six warm absorber components found by previous analyses .
The RRCs allow us to directly calculate a temperature of the emitting gas of a few eV ( \sim 10 ^ { 4 } K ) , favouring photoionised conditions .
We fit the data with a Cloudy model of log \xi = 1.45 \pm 0.05 erg cm s ^ { -1 } , log N _ { H } = 22.9 \pm 0.4 cm ^ { -2 } and log v _ { turb } = 2.25 \pm 0.5 \mathrm { km s ^ { -1 } } for the emitting gas ; this is the first time the X-ray NLR gas in this source has been modelled so comprehensively .
This allows us to estimate the distance from the central source to the illuminated face of the emitting clouds as 13.9 \pm 0.6 pc , consistent with previous work .

Conclusions :