How to remove the ”barrel” type air filter on the 150?

It appears to come out sideways, into the wheelarch, after removing a cover plate😱…
I want to put short trumpets with foam filters, or the pancake filters.
The engines in the 2 cars in question run very well, but might run even better with a change.

Hello Peder,
I installed a foam filter on my XK150, on the aluminum input piece.
Just where now the “barrel” filter is ( it was already removed when I bought it )
This way it looks more original.
And there is more room for a large foam Filter.
Peter Jan