Reform Gaining Huge Numbers Of Votes...
News14 mins ago
No best answer has yet been selected by ragtagbob. Once a best answer has been selected, it will be shown here.
For more on marking an answer as the "Best Answer", please visit our FAQ.It sounds like the field drain could be 'silted up'. The quick fix would be to hire a drain company to flush it but that's only a temporary solution. You really should have it dug up and re-laid with, at least, 14mm dry chippings surrounding the pipe. (Wrap it in 'Terram' weave sheet to be completely sure it doesn't happen again).
Another option to consider would be to built a 'well head' at the source of the spring to channel it away from your underground drainage. That'll reduce the load on the drain and help to reduce the 'silting'.
Hope that helps.. Let me know how it goes. I had a simmilar problem and the new drainage helped me.