Yeah, im going down the neighbor route first and if there having none of it then it falls back with the builder, im paying nothing towards this lol, i asked him about it last week and he says its a blockage further up the line backfilling into the chamber and now leaking out the top, the neighbor does have alot of trees and shrubbery along his boundary the same boundary the pipe runs along so its sort of inevitable its going to be blocked some how with roots.