I saw how expensive decent water diverters were, so thought I'd make my own.
It has a ½" BSP thread for connecting hose fittings to.
I designed it so you can cut a 80mm section out of a down pipe, slide the top in place, and then it should drop down onto the bottom one.
You could add some sealant, but this allows servicing and unblocking if you ever need to.
The author marked this model as their own original creation.