Solar PV spacing/how much space is required

[BISFBath]

Hi all,

I am having my house reroofed and afterwards planning to have solar PV fitted. I have an installer who has quoted for 12x Hyundai 400W panels.

Does anyone know how much space these require as the roof size seems pretty marginal to me. It is a simple pitched roof on an semi-detached house (ie joined to the neighbouring house at one end with a gable at the other, no hips, valleys etc). Each side is 7050mm long (neighbouring house to gable) and 4200 mm wide (gutters to ridge). The ridge is aligned roughly east-west so only the one, south facing, side would be used.

The spec sheet gives the module size as 1719x1140 mm, so assuming two rows of six panels portrait layout and say 20 mm (?) between panels that's 6940 mm. Is that enough room? Not sure what the panel spacing is or how much room needs to be left at the gable or join with neighbours. If it's only very slightly too little I may be able to have it increased slightly as the gable needs overboarding anyway with battens and fascia etc.