What I can’t tell you is anything much else as Swan is an own label brand for GUS and there is no technical or spare part support for the brand whatsoever.
Basically, if it’s out of warranty there’s nothing much you can do with them bar deliver it to the local council recycling centre.
Turn the whole appliance off for 48hrs with both doors open and then restart as normal. It’s possible that one of the doors have not been closed correctly. If it works great.. If not then spend more to get a decent appliance.