In Pembrokeshire, Jules Hudson joins Sea Trust Wales to help photograph porpoise as part of vital conservation work and gets hands-on with the Recycle Mor project. On the North Tyneside coast, Helen Skelton takes the plunge at Tynemouth Long Sands, which is fast becoming the North-East's surfing hotspot. JB Gill traces the journey of Norfolk-grown mustard from farm to factory on the Norfolk coast