There is only one reason that race numbers (or any other graphic) pulls the paint off. That is that the glue adhesive used for the graphic is stronger than the paint adhesion to the car.
If the car is painted properly, no amount of adhesive on the graphic will pull the paint. Starting from bare metal, the surface must be abraded and de-greased properly, the primer coat must be applied in the correct environment, the topcoat that follows should either have a chemical key (strict temperature and overcoat times to be adhered to) or be mechanically abraded between the primer and top coats. Finally, the topcoat must be "baked" off in a temperature controlled oven.
It's our own fault that the paint comes off and I don't think any blame should be passed to Caterham / TSK or anyone else who paints Caterhams. The reality is that none of us wants to pay what it actually costs to paint our car properly so we end up getting what we pay for. I wouldn't do it for less than £4K plus VAT and you'd all laugh at me if I quoted that.
You can help the paint work out as others have said, by applying wax on the paint before the graphic and by using heat on removal. Either that or put a white background on the car and live with the fact that when you eventually remove it, you'll be in for a re spray.