There are three seals on this model for the door. 
A lower door seal for the bottom of the door. 
A main door seal.
A dispenser seal.
It could be any of them but as the can be bought for between £7 to £10 I would replace the lower and main seal. 
The main seal is an easy push fit but I have forgotten how I replaced the lower seal.
                
 JD
                
 July 2014