Outdoor twin fridge cupboard (large pics!)

[JabbA]

I've acquired a wine cooler (for fermenting and conditioning) and a fridge (laggering) from freecycle but haven't room for them in the shed. What I'm planning is a cupboard behind the shed made from 50mm Kingspan sheet roof insulation and treated timber. What I'm unsure of off is the amount of ventilation needed, would a gap of around 200mm at the rear and top venting to an 80mm gap be enough?



Any thoughts?

Cheers,
Jamie

[Scooby]

Built under fridges and freezers inside only have minimal ventilation, mine has 2 grilles about 20cms x 6cms each venting through the plinth, what you suggest sound ok to me.