Try Jandi first.

Plump your cushion, make a big mug of tea and have a generous stack of ginger nuts to hand before you ring them up.

Pete²

Hi Pete and welcome to Eribafolk.
I should think that the drawer on all Eriba Touring models of roughly the same age as yours will be the same size although I'm not sure.
The best place to start would be to phone Jandi http://www.eribacaravans.co.uk/ as they have a comprehensive knowledge of all Eriba models.
They will probably ask you for serial numbers etc for your van which you'll find on the plate on the outside of the van just in front of the door bottom.
Hope that helps
Randa
Sorry Pete, but Pepe (Pete) got in before me...