Sean Fletcher, Margherita Taylor and Steve Brown are in Northern Ireland. Sean is at the beautiful Lower Lough Erne meeting the two boat-building brothers reviving the traditional clinker boat. He sees the intricate way they are made and gets to sail in one - the first time a wooden clinker boat has set sail on the Lough in decades. Margherita explores the boom in pine marten numbers in Fermanagh and finds that, while it is good news for the local red squirrel population, it is bad news for smallholders. And Steve Brown heads to Killeter, where the local churches are putting on a very special display to mark the 200th anniversary of the birth of Cecil Frances Alexander, writer of All Things Bright and Beautiful. Also in this programme, Tom Heap meets Sir James Dyson and hears his vision for the future of British farming. Adam Henson does a bit of spring stock-taking down on his farm, and John Craven is joined by Cerys Matthews and Simon King for the launch of the Countryfile Photographic Competition for 2018.