You've probably already seen this picture

https://www.sungreen.co.uk/Lydbrook/Lydbrook-House-1966.htm

It shows the house is right below the old viaduct. It can be found on this map

https://maps.nls.uk/geo/explore/#zoom=18&lat=51.8495&lon=-2.5875&layers=178...

And here it is now on Google street view.

https://www.google.co.uk/maps/@51.8495693,-2.5876223,3a,39.2y,270.04h,90.59t/data=!3m7!...