Waste firms based in Wales register with Natural Resources Wales rather than the Environment Agency; a firm based in England working here holds an Environment Agency registration instead, and either is valid across Great Britain. Each Welsh council issues its own skip permits for its roads, with its own fees and notice periods. The skip company normally applies for you; ask whether the cost is included in their price.
For a specific area see skip hire in Cardiff, Newport, Swansea or Barry. For anywhere else, search your postcode to see which suppliers cover it. The size guide works out the size from what you are clearing and how heavy it is.