Though single catalexes generally go unremarked, multiple catalexis will sometimes obtrude itself upon a critic's attention, in which case it will tend to be interpreted prescriptively as a departure from metricality.
It is interesting that Lowell and Larkin's rediscovery of catalexis has not caught on among subsequent users of the pentameter to the extent that one might have expected, even among Larkin's acknowledged poetic disciples like Anthony Thwaite and Douglas Dunn: the roots of prescriptivism run deep, and nobody wants to be awarded the asses' ears as one of Ghose's "incompetent poets" who cannot count up to ten.
This line can only be iambic, because trochaic tetrameter (perhaps being too recent a form to have developed conventional variations) does not tolerate inversion, internal catalexis or hypermetricality:
Here catalexis has the incidental extra effect of clarifying the grammar: the syntactic break it draws attention to shows over empty chairs to be an adverbial modifying the verb spreads, rather than a postmodifier of the noun lights.
The reading increase is Larkin's (on tape); the more usual increase would create a second catalexis (the brackets indicate reversal of stress pattern under the Rhythm Rule).
Again, most of the structure and rhythm is unmarked, so we are left with little to notate overtly except the catalexis.
Unless the catalexis we find regularly is demonstrably the byproduct of something else, we can simply note the markedness of the situation with a constraint violation.
For this reason we should discuss why the catalexis is initial and why the meter is better analyzed as iambic than as trochaic.
But if we assume that the catalexis is initial, the positions of the caesura and bridges line up exactly and we find an understanding for how these two meters could be freely mixed in with one another.
This makes it even more marked than the trimeter since the unmarked case (acatalectic dimeter) is to have two metra to the line and no catalexis.
Candidate (a) has final catalexis and consistent violation of NOLAPSE, as desired, but removing the final metrical position leaves an L as last position, in violation of ANCEPS.
1) and then review our proposals for understanding line length, rhythm, and catalexis in Greek meters and beyond (section 6.