This is a Premier Route. To claim an FKT on this route, you must meet a high standard of documentation and verification. See details here: https://fastestknowntime.com/premier-routes.

The South West Coast Path is the longest walking path in the UK. It runs 630 miles along the southern and western coasts of the UK, through Dorset, Devon, Cornwall and Somerset. The SWCP has seen several FKT trips in recent years. Here's a summary from Damian Hall's post on the inov-8 blog (with links added):