I completed the Welsh 3 Peaks solo and unsupported. A friend had asked me to join an organised Snowdon Midnight climb last year to raise money for Alzheimer's Society. We didn't do it in the end (as my friend emigrated) so I committed to find a challenge to raise money anyway. I'm a qualified ML and familiar with the peaks, so this looked a good level of challenge and achievable in a day.
12 hours and 15 minutes
The Welsh Three Peaks Challenge involves climbing Snowdon, Cadair Idris and Pen y Fan in the same day, either over 24 or 12 hours.