Sorry but I agree with Dave on this one. Audio quality shouldn't be a barrier to submission, but everyone should aspire to make recordings that are 1) clearly audible at normal playback volume and 2) are not distorted or clipping. These criteria do not exactly constitute BBC-level standards. I don't care that much in the end. If the audio quality doesn't meet my 2 (very basic) criteria, I just delete that episode and wait til the next day for another one. 

Incidentally Auphonic is an excellent tool that can help with this and requires no technical expertise. I'm not advocating it necessarily, but it's one very easy way to improve audio. 