This has been solved, after a solid 15 hour sit down. As I thought, the solution was quite simple. I'll post the code below for anyone else who has this issue in the future.
//Sets the down walking animation stopstart
if GetRawKeyPressed(83)
CreateSprite(1,1)
AddSpriteAnimationFrame ( 1, LoadImage ( "Down(1).png" ) )
AddSpriteAnimationFrame ( 1, LoadImage ( "Down(2).png" ) )
AddSpriteAnimationFrame ( 1, LoadImage ( "Down(3).png" ) )
AddSpriteAnimationFrame ( 1, LoadImage ( "Down(4).png" ) )
PlaySprite ( 1, 10, 1, 1, 4 )
DeleteSprite(7)
DeleteSprite(11)
DeleteSprite(15)
elseif GetRawKeyReleased(83)
StopSprite(1)
endif
//walkleft
if GetRawKeyPressed(65)
CreateSprite(7,7)
AddSpriteAnimationFrame ( 7, LoadImage ( "Left(1).png" ) )
AddSpriteAnimationFrame ( 7, LoadImage ( "Left(2).png" ) )
AddSpriteAnimationFrame ( 7, LoadImage ( "Left(3).png" ) )
AddSpriteAnimationFrame ( 7, LoadImage ( "Left(4).png" ) )
PlaySprite(7, 10, 1, 1, 4)
DeleteSprite(1)
DeleteSprite(11)
DeleteSprite(15)
elseif GetRawKeyReleased(65)
StopSprite(7)
endif
//walkright
if GetRawKeyPressed(68)
CreateSprite(11,11)
AddSpriteAnimationFrame (11, LoadImage("Right(0).png"))
AddSpriteAnimationFrame (11, LoadImage("Right(1).png"))
AddSpriteAnimationFrame (11, LoadImage("Right(2).png"))
AddSpriteAnimationFrame (11, LoadImage("Right(3).png"))
PlaySprite(11,10,1,1,4)
DeleteSprite(1)
DeleteSprite(7)
DeleteSprite(15)
elseif GetRawKeyReleased(68)
StopSprite(11)
endif
//walkup
if GetRawKeyPressed(87)
CreateSprite(15,15)
AddSpriteAnimationFrame (15, LoadImage("Up(0).png"))
AddSpriteAnimationFrame (15, LoadImage("Up(1).png"))
AddSpriteAnimationFrame (15, LoadImage("Up(2).png"))
AddSpriteAnimationFrame (15, LoadImage("Up(3).png"))
PlaySprite(15,10,1,1,4)
DeleteSprite(1)
DeleteSprite(7)
DeleteSprite(11)
elseif GetRawKeyReleased(87)
StopSprite(15)
endif