Had it emptied today, I reckon its been repaired before with a new raising piece jammed in, hence why it looks distorted.
https://s23.postimg.org/cyp369d3f/st1.jpg
https://s29.postimg.org/wyfm5wfs7/st2.jpg
https://s29.postimg.org/tpih5wxlz/st3.jpg
https://s29.postimg.org/6bt73z5yf/st4.jpg