Thanks Noel - the rendered file was played in Windows Media Player with BIAB closed. The file itself is being slowed down. If I simply drag the parts across to the render box on the manipage (top left) the WAVs are fine. I didn't use the MP3 there as I was unsure of default bit rate. It's why I used it under the Audio tab

1. answered in the OP
2.ASIO
3. 48kHZ
4. didn't check