Have you actually tried Google?
There are a plethora of options and kits available from a multitude of retailers.
example:
Get your DSLRPros Inspire 1 FPV Camera Upgrade from one of the top industry leaders in UAS sales, with top-rated customer service.
www.dslrpros.com
or seeing as you are UK based:
The DJI Inspire 1 is an amazing and versatile quadcopter, especially in the dual controller form. Now Heliguy are making it even better with the option to upgrade it by adding a first person view (FPV) camera and monitor. The Inspire 1 boasts an ultra-high definition 4K camera which can rotate...
www.heliguy.com
There are also numerous threads already on the subject.
Like this one:
Hello there, I have been thinking about adding fpv to the inspire 1 for quite a time now. What has been holding me back is how I wanted to do it. I recently decided to paint my inspire 1, and at the same time, I did the fpv mod. Heres how I did it, parts ive used and problems that came along...
inspirepilots.com
Moved to Inspire 1 section