On 2 April 2021 Si Smith competed against a relay team of four over 37.5 miles on the Mynydd Epynt. He finished the run in 5hrs 16 mins and 23 seconds beating the relay team who finished in 5hrs 24 minutes. The event raised funds for Brecon Mountain Rescue and finished with £3200 for the cause. Si had a safety vehicle ahead for the whole route with Mr Steve Walton and Mr Terry Jones who witnessed the whole thing. They set up mobile checkpoints with water and gels to support the effort. The relay team consisted of Damien Thomas, Richard Bullass, Paul Wesley and Patrick Buckley who are the fastest known relay team over the distance. It is likely that an individual and relay team will attempt to beat these records next year to raise funds for Brecon Mountain Rescue