Apex writes - Ximenes died on June 29th 1971.  After all of his prepared puzzles had appeared, The Observer published four IN MEMORIAM puzzles which had been set by solvers.  I knew nothing about these until the first one appeared.  I then set this IN MEMORIAM puzzle and submitted it, but it was too late for publication.  As far as I know the poem of four verses has not been included in any anthology. . Solvers interested in knowing more about it, should be able to complete the verse and discover the name and address of the poet, by decoding the pairs of letters which are governed by a PLAYFAIR CODE SQUARE with a key-word derived from the letters entered in the shaded squares. The key-word also appears in the verse.

In Memoriam by Apex

The 36 letters of the last 9 words of a modern poem (very suitable for the occasion but a bit too modern for X to have enjoyed) should really occur (in some cases more than once) in the answers to the clues.  The first in 1 ac, the second in 6 ac, and so on in the right order up to the last letter, which should occur in 30 dn.  But these letters must all be omitted, wherever they should occur, when the answers are entered.  Definitions in clues refer to the full, unmutilated words (lengths indicated by numbers in brackets); subsidiary indications refer to the mutilated forms to be entered in the diagram. Chambers Dictionary is recommended.
Across
1. Gossip, after one left, was probably evil (12)
6. Duck about to suffer in the country (6)
10 Sweet girl appearing in endless dreary ITV breaks (12)
12 A hermit settled in tower (8)
13 Opening I take to make a successful putt (7)
14 Old couple no longer to complain (5)
15 To propel Scots in a boat-shaped structure (6)
16 Speech, Heath's first one sounded superior (8)
17 Drink Scotch if rank is reduced (9)
23 Bear ate terribly spongy buns (8)
24 Can one be ruined with a tin of tobacco? (8)
26 Dealer to cope with screeching mother (6)
28 Japanese coppers arresting married sailor (6)
29 Consoles in organ one services (7)
31 Wild cit out of control - a dotard (8)
32 Producer of sham prints - I hated every one (12)
33 Dwarf frequently turned handle with a light noise (6)
34 These may be used for killing birds without weight (7)
Down
1. Vividly clear, fish before a spasm (7)
2. Badly nip heel of red deer (8)
3. Small bill for a padded jacket (5)
4. Take everything up in praise of old idlers (8)
5. Unrefined sugar upset a deacon (9)
6. Like a tablet? - leading performer swallows fifty (6)
7. Of the smallest I'm one in almost half a million (7)
8. A difficulty - ending of 147 frame among English players? (12)
9. Cautious about being trapped in a net (7)
11 Ravenous creature, heartless prowler with peculiar look - I flew out (11)
18 Drumming sound - scope in a beat is endless (8)
19 A rock concert one is at? (8)
20 These carry many a Royal Society round old railway line (9)
21 Prodigy on the way - appearing before Royalty (7)
22 Perforated plate isn't left about carelessly (7)
25 Cut diamonds around one head of State (6)
27 To rate one ship with another (6)
30 Shop has to display original form of seat (5)

Coded Verse "YCKNZLDHLUNTEGTFTFGWLTKZ _ _ _ _ _ _ GLCBGMCUTSFITIPOTNQETLKM HRLTXFHRNTMTRKGK_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ O.D.GLVRIT (RYKHNB)

Complete verse - - - - _. _. _ _ _ _ _ _ ( _ _ _ _ _ _ )