Bringing up a newly-acquired 2004 3.0, so put in a new cabin air filter yesterday. I use Amazon for a lot of parts so chose one from their selection for less than $20. Mann Filter CUK 5141 is equivalent to the OE Jaguar part; they also have installation instructions. I did not remove the wiper arms to free the entire cowl cover. I did vacuum out leaves and dirt from the filter housing before buttoning up. The filter I removed was about two years and 15k miles old, and is not the activated charcoal design of the new piece.

 

When doing mine, the strip under the cowl tore off near the ends. When looking on eBay for replacements, I noticed that the weatherproof strips on the eBay parts were also torn off.

I used some exterior grade 2" black electrical tape to seal the cowl, which is a jaggedy kludge, but keeps the water out (and doesn't look very noticeable at all.)

I have a theory that much of the issue people have with water getting into their ECU's and TCU's is driven by a missing weather strip seal under the cowl.

 

Here is the TSB from years ago.

bob