The saga of my son's summerhouse continues. He has fitted the shingle
roof over the leaky wooden original, so now he needs the gutters to
dispose of the now-external water.

He went to Wickes and bought some brown Miniline 76mm gutter, but they
didn't sell any 135degree corner pieces.

He went online and found this (or something exactly similar) also called
76mm miniline

http://tinyurl.com/o4cx9jo

When you push the gutter into the corner piece, it is loose. Is this
right? I thought it should clip together. Have we missed something
obvious?

Alternatively, it looks to me that, if some of the rubber seal could be
stuck to the outside of the gutter, it would make a tight fit. Is self
adhesive rubber seal of this type sold?
--
Bill