Neighbours gutter overflowing into our garden

[mcprinter]

Fairly new neighbours. We get on pretty well and would like to keep it that way.
Ideally would like some ideas before speaking to them.

Their house is 90 deg to ours at the end of our fairly small garden.
Replaced a fairly scruffy lean to with a decent single storey side extension with pitched roof. We are happy with the change.

There used to be a downpipe at the front of their house but due to extension have downpipe discharging onto the pitched roof into a gutter on the extension.
Not 100% sure on any other downpipes.
Gutter on the extension runs across the back of our garden.

Any heavy rain and the gutter overflows into our garden
Torrential rain the other day and it was like a waterfall and washed a quite lot of our soil away. The wall of their extension also soaked 4-6 feet across.

Are there any easy/cheap fixes?

Think it is standard guttering. Would deep flow help?
Any way to spread the discharge from the downpipe over a wider area of the roof? The shoe points towards the gutter.

Came across this. Any use?

RoofArt Galvanised Steel Guttering Overflow Element 180° - 125mm

Crafted from high-quality galvanised steel, it delivers unmatched durability, corrosion resistance, and a modern, low-maintenance finish. Seamlessly integrating with your existing gutter system, RoofArt Galvanised Steel Guttering Overflow Element offers superior performance and enhanced...

www.roofingsuppliesuk.co.uk

 

[blup]

Surely reinstate the original gutter to distribute the rain load, and review. Its potentially a legal nuisance if water discharges like that onto your land and the onus is on them to remedy it.

Blup

 

[mrrusty]

It does sound like the remedy could be a much deeper gutter section. I'd have a chat to them - they may not realise their wall is getting soaked as well. Certainly not worth falling out about a bit of gutter replacement.