Vacuum mounts 2004 V70

Hello and I'd like to firstly thank admin for accepting me into the forum.
I have a 2004 V70 with 265.000 miles on it and recently it has started to idle rough. I have changed the mounts on the cross bar and at both sides of it....Iv changed the side engine mount,...the gearbox to engine mount and also the 2 vacuum mounts...all new I bought the vacuum mounts...which were new... from a guy who no longer needed them as he had sold the car before fitting them but he had taken out the 'rubber inserts' where the pipe plug goes in. The inserts on mine are perished so I can't use them. I have contacted the manufacturers of the vacuum mounts asking if they would supply me the inserts but they said that they only supply full mounts. Does anyone know where I could get these inserts as I think it they are the reason that engine idles rough.....sorry for the long question
Thanks
Kevin.