gurgling bath plug hole

[jerrythemole]

I have a problem with a gurgling bath plug hole. My bath is fitted with a shallow trap ( no room for anything else) which then runs for about 6 feet to a sweeping T where my wash basin with a 32mm bottle trap, connects. The pipe then runs for about 2 feet into the soil stack. All the pipe is 40 mm except for the connection to the basin which is 32mm. Both the basin and the bath drain very well but when I drain the basin I get a gurging noise coming from the bath. I have not noticed any smell coming from the bath plug hole. Any ideas how to cure this would be appreciated.

Thanks

 

[seco services]

fit an anti syphon basin waste

 

[jerrythemole]

Thanks for your answer, I will get one tomorrow