I have a rainwater downpipe which comes down from a gutter and discharges
onto a sloping tiled roof below a dormer window. At the bottom edge of the
roof is another gutter with, naturally enough, its own downpipe. All this
in conventional uPVC.

When the rain is heavy and the wind strong, the run-off from the
intermediate downpipe is blown off the edge of the tiles and cascades down.
I'd like to add an extra pipe run to direct the water straight into the
lower gutter, but is there a reliable way of fixing it to the (heavy clay)
tiles? Are there custom-made clips or similar? Or a practical DIY
solution?

Many thanks.