Bosch S4 & S5 are the same size like for like the 4 is blue & silver with 4 years warranty the 5 is all silver with 5 years warranty ...
If its a 019 battery code it will fit the 019 is standard fit size on 2.5 tdi battery tray is the same ... Hope this helps
My friend gave me a Bosch S4 100ah - I couldnt see how it would fit in my 2.5TDi due to the air-conditioning pipes being in the way.
There is an 85ah unbranded battery in there at the minute and looks like the maximum width that will fit.
The Bosh batteries are the dogs danglies though - the S4 battery my friend gave me was made in 2006 - been sat on the garage floor for 2 months, thought I would give it a trickle charge - it jumped from 12.4v to 14.4v in about 4 seconds - the charger turned off!