Resolved by adding the below 'path' attribute to the generator SpecFlow config section
<generator path=".\lib"
full config
<specFlow>
<generator allowDebugGeneratedFiles="false" allowRowTests="true" generateAsyncTests="false" path=".\lib" />
<runtime stopAtFirstError="false" missingOrPendingStepsOutcome="Ignore" />
<trace traceSuccessfulSteps="true" traceTimings="false" minTracedDuration="0:0:0.1" stepDefinitionSkeletonStyle="RegexAttribute" />
<plugins>
<add name="McKeltCustom" path=".\lib" type="GeneratorAndRuntime" />
</plugins>
<stepAssemblies>
<stepAssembly assembly="SpecFlow.Assist.Dynamic" />
</stepAssemblies>
</specFlow>