For VW T5 T6 Transporter Sounds like a Golf Door Seal and Dash Trim Combo
£14.58
T5 T6 Door Seal and Dash Trim Combo. This rubber is fitted to high end T5’s and T6’s it sits between the cab door’s and the body of the van. Its purpose is to make the door sound quieter and shut with more of a clunk than a rattle.