Hi! We've booked a Keycamp holiday to Lake Garda in July. Just discovered today I can't hire linen in their supertents. We'll be flying so I'm a bit worried about what to take in the way of bedding. Ryanair will allow us 15kg each.
It will be pretty warm there in July so you wouldn't need a thick bag - the first one on this page weighs 650g, it's a 1-season bag. £30 though - I wonder what Ryanair charge for excess baggage? I would try weighing the linen you would choose to take and find out how much it would cost you to take it along - probably less than £30 a head!
(OTOH this one from Argos is less than £7.50 but it doesn't say how much it weighs.)
not sure about keycamp, but eurocamp give you pillows and blankets, so you only need sheets and pillow cases anyway. We went to Lake Garda in June and never took the blankets off the shelf though, it was so hot.