does the DPF fail on Jaguar vehicles? Where can I get a statement on its reliability?

DPF can fail on any vehicle.

What age and mileage is it?

What year is the car? How many miles has it done? When did you buy it, and where from?

DPFs can fail, the internal matrix can break loose or break up, allowing exhaust gases to pass freely, which will throw a fault code because the pressure across the DPF will be outside the parameters that are acceptable to the ECU. A very simple test for this is: is the exhaust tailpipe sooty? If you wipe a finger inside the tailpipe and it comes out black with soot, the DPF matrix has failed and the DPF does need replacing.

More usually, a DPF pressure or temperature sensor fails, which the ECU will show as DPF failure on the dash but a scan of the fault codes will show the specific sensor problem.

Many garages either cannot, or will not, diagnose DPF issues properly because they don't really understand how they and their relevant sensors work. You really need to get the precise fault codes from the garage and post them here, so we can advise further.

Have you just bought this car?

Google 2.0 Ingenium problems.... Since you have only done 600 miles, would suggest you have recently bought it, if less than 30 days then reject it - and buy something that doesn't have that engine in it!

garage say DPF a not a consumable like brake pads , clutch etc.

Garage is wrong. Its not a lifetime part.

Treat it like an exhaust, but with a slightly longer lifespan.