Look behind the air filter housing and see if you have the ABS pump. Alternatively, if ABS then when you start the Disco you will see a yellow ABS light come on and stay on until you reach 5 MPH then it goes out.
 
Yes, mine has ABS and it's a pain in the arse and a nightmare to get an 'off the shelf' snorkel. There are plenty of non-abs snorkels around.
 

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