Sandwich Sudoku

In Sandwich Sudoku, the puzzle is presented with extra numbers outside the grid next to each row and column. These numbers indicate the SUM of cells sandwiched between the 1 and the 9 in that row/column. The logic required to solve the puzzles will appeal to anyone who enjoys normal sudoku and a bit of basic maths. Each puzzle here has been lovingly hand-crafted by Mark Goodliffe and Simon Anthony...