Pen y Fan is Wales’ second largest mountain and the highest mountain in southern Britain, standing at 886m above sea level. It’s a popular National Trust location, with over 250,000 people tramping up to the peak each year. At the top you are rewarded with dramatic steep slopes and valley scenery and with the right conditions, you can see right across the four counties of Herefordshire, Gloucestershire, Glamorgan and Somerset. We chose to climb Pen y Fan with our toddler and preschooler as part of our four-month challenge. Here’s how we go on.