Any ideas anyone? Thinly rolled out layers, made of gumpaste? 

I would say thinly rolled out layers of fondant, not gumpaste.

Wrap the strips of paste around the cake starting at the top and working down. Use edible glue to attach the strips.  There should problem with the thin strips staying upright if the bottom half is adhered to the cake.  Good luck!

AI would personally (carefully) flip each tier upside down after the base layer of fondant has set. I'd then apply each strip of fondant - starting at (what now is) the bottom. That way you are not working against gravity. Leave for an hour or so for the fondant to 'set' slightly and then carefully flip the right way up and then dowel & stack. This would ensure that the strips of fondant stay upright.

I would not flip the cake upside down for this technique For the Maggie Austin technique, yes but not necessary with this.  I would make the curved strips about 6" long out of fondant and adhere with edible glue.  I would also use a pasta machine to make my strips are all the same thickness.  Start at the top and you can gently curl with your fingers.  As you move down the cake just make sure your strips don't line up so you get that ruffly look.

Hope this helps :)

I've done cakes like this and you can also use a buttercream cake and attach the strips with buttercream. No reason to turn it upside down.

Brilliant! Thanks so much everyone! It makes sense now. Have just sent my quote off so if they go with me I'll be sure to post piccies. Thankoooo!