I don''t think there is enough information for a unique solution. If the average is 73 then the total must be 365.
If for example L pays £20 then T pays 15, M pays 30 and E pays 60 leaving K to pay the remaining 240.
But if L pays 60, T pays 45, M pays 60 and E pays 120 leaving K to pay the remaining 80. Both valid scenarios.
Unless I'm missing something or it is a non-mathematical puzzle.