leaking handbasin bottle trap?

Bottle trap similar to Crosswater Millennium Chrome Bottle Trap taken apart by a tiler now leaks around the collar where the basin outflow enters the top of the trap, there were no washers or gaskets around the pipe under the cap when i dismantled it, dont know if there were previously, have tried all sorts of gaskets and sealers to no avail. The drain pipe from the basin enters the top of the trap and slides into a plastic inner sleeve, as i see it the water is hitting the bottom of the trap and some is being forced back between the pipe and plastic sleeve resulting in seepage around the hole where the pipe from the basin drain enters the top of the trap. Any ideas ?