callResult.ShouldBeEquivalentTo(centreResponse,
                                opt => opt.Excluding(r => r.DateOpen));

callResult.ShouldBeEquivalentTo(centreResponse, opt => opt
          .Excluding(r => r.DateOpen)
          .Using<string>(ctx => CompareStrings(ctx)).WhenTypeIs<string>());

public void CompareStrings(IAssertionContext<string> ctx)
{
    var equal = (ctx.Subject ?? string.Empty).Equals(ctx.Expectation ?? string.Empty);

    Execute.Assertion
        .BecauseOf(ctx.Because, ctx.BecauseArgs)
        .ForCondition(equal)
        .FailWith("Expected {context:string} to be {0}{reason}, but found {1}", ctx.Subject, ctx.Expectation);
}