When building a house, it seems nowadays this creates as many choices as there are in a supermarket: you draw what you want and we can build it. The supermarket has at least pre-packaged items. You want potato crisps? Narrow it down to organic, slightly salted, healthy and a few brands remain.
With rainpipes it is different and there are a few routes:
Reinventing the rainpipe. How does the water really flow and would changing the flow of the water shape the rainpipe (Assuming that water hasn’t changed much over the last millennia, is this perhaps a slightly arrogant route: who am I to change the course of water.)
Look at different solutions globally: in Japanese temples the water comes down a chain. This was also used by the architect Aldo van Eijck, but would result in cultural appropriation these days. As the new house is in a coastal area, with a lot of wind this solution may not be so good as the wind will blow the water off the chain.
Look around. This is what I have done. Near Morden, an industrial building, huge brickwall with square rainpipes coming down. In our victorian terraced street: rain pipes coming down in many materials, straight from a gutter, no hoppers. Many services to Victorian houses were applied after the houses were built, so the facades are often decorated with all kinds of pipes and wires which once represented progress.
Examine what the building needs: it is not an isolated problem and should make sense with the rest of the façade.