Post hike report as requested Fionn!
It was a hike organised by the Outward Bound Association in NI - £10 to enter and it goes towards bursaries for outdoor pursuits etc. You could do a 10 mile or 20 mile treck (in a fit of madness I decided on 20). We walked from Rostrevor along the Ulster Way (which follows the road inland along the Rostrevor Forest) then on to Windy Gap, followed the wall up Slieve Moughanmore (steep!), down the other side and up Pigeon Rock Mountain, then through about a mile of rushes and bog to Spelga Dam. Spelga was the stop for the 10 mile hike. We had lunch and a sock change at Spelga then set off across Butter Mountain, along the Ulster Way by Fofanny Dam, followed the Mourne Wall to Trassey, walked down the Trassey Track and into Tollymore Forest Park, and then through Tollymore and into Newcastle, ending in Donard Park. I was in a group with my current Significant Other and a couple of friends from work. We walked it all in about 8.5 hours (that includes a half hour stop for lunch). They gave us a can of coke and a medal at the end! A medal! Last time I got a medal it was for runner up in the Slip Jig when I was about 10 years old. Anyway, it was a beautiful day. The sun shone the whole time, the company was great and there must have been about 300 people in all enjoying the spectacular scenery of the Mournes. It wasn't the most picturesque route to take, but it was great fun and a very enjoyable day.