3 bolt exercise bike saddle adapter in the UK

The saddle currently fitted to my exercise bike is attached to a fixed plate with 3 bolts on it, I can’t find any adapters to fit more traditional saddles (rails/posts) that are available in the UK. The current saddle is criminally uncomfortable and I would really like to replace it with a more traditional saddle designed for comfort.

My current bike:
https://www.argos.co.uk/product/4026004
“Roger Black Gold Magnetic Exercise Bike”

Adapter style that I need(not available in the UK and they don’t ship outside of US/Canada.
https://www.amazon.co.uk/FitDesk-Saddle-Adapter-Universal/dp/B00M24K97G

Does anyone know of any UK based company/bike shop that could provide an appropriate adapter for this style of fitting by any chance?

This is my last resort before I have to go out and buy a new bike.

Thankyou in advance.