Are we talking about a prior art search or about a Freedom-to-Operate search?

I have never in my lifetime seen someone do a prior art search for designs unless we wanted to file a revocation request against an existing registered design.

The reason for that being that the scope of protection of a registered design - different from a patent - is usually only determined during litigation proceedings in court.

In practice we never ask whether a design is novel prior filing. Even if there are similar designs in the market, the patent offices will never examine for novelty of registered design applications.

So we just file what we have but we must tell client that they may face revocation proceedings later. Which will never happen. "Never" as in "very likely never".