Thanks, the appsetting worked great.
Mariette, could you post your config section for the blowery module? This was mine:-
    <httpCompress preferredAlgorithm="gzip" compressionLevel="high">
      <excludedMimeTypes>
        <add type="image/jpeg"/>
        <add type="image/gif"/>
        </excludedMimeTypes>
      <excludedPaths>
      </excludedPaths>
    </httpCompress>