The feed www.ukpornpodcast.co.uk/feed/podcast/
is empty, so that is a problem. This is your podcast only feed, both from PodPress and also in PowerPress. Remember PowerPress started out as a fork of PodPress, and we promptly rewrote it after struggling to fix major fundamental issues with PodPress. We designed it to replace PodPress because we were all at one point using PodPress.
The feed http://www.ukpornpodcast.co.uk/feed/?post_type=podcasts
is a custom post type feed. PodPress, up till the past year, did not support custom post types. It's current solution is most likely buggy at best since custom post types in WordPress are still maturing. PowerPress under normal circumstances will import the episode data, but the problem with custom post types is the post type meta data is not accessible to PowerPress, so you're kind of stuck with PodPress at the moment.
I would recommend you consult with who ever helped you or advised you to use custom post types. Custom post types are confusing, complicated, and in most cases, are not used for what they were originally intended for.
We have a feature in PowerPress called "Podcast Channels", which can work with or without custom post types. The most important feature of PowerPress's podcast channels feature is that it can work independently of the custom post types so you do not have to deal with these problems.
If you would like our assistance with your problems, you can hire us as consultants. If you're interested, please use the contact form www.blubrry.com/contact.php
with more details of your setup and we'll schedule a consultation.