If they're not perished or damaged they probably just need installing correctly.
The seals on wooden frame uk caravans are tacked or stapled to the frames, but with the Eriba's steel frame this method isn't possible.
I've replaced seals on some older Eribas (up to about 2006) and the seals on these have been fixed with brad nails shot into the frame with a nail gun.
When fitting new seals I pop-rivet the seals to the frame - it's a bit time consuming as the seal and frame need to be drilled first.