Ev N0. 1631 ( Missing ) By Eclogue

[Matakari]

With lots of help, I’ve got a maximum of 14 missing letters out of 28, insufficient, I think, to make further headway. I’ve solved on my own 16 clues without being able to determine the missing letters for them. They are the following and I would be happy to know where the missing letters are for them, thanks in advance:

ACROSS: 13(Asps); 15(Oeillades); 16(Tusche); 17(Ring Up); 18(Outleap); 25(Retract); 26(Coacts); 27(Zsa Zsa); 29( Niellated); 36(Synod)
 

DOWN:  5(Unclear); 9(Uses Up); 10(Dry Up); 19(Lacerta); 24( Bonito); 30(Ecco)

(Four answers must be modified before entry to reflect an historic event. In 28 other clues there is a letter MISSING in the definition; in clue order, these letters provide a similarly thematic name (2 words) and an object ( 3 words ). Once the grid is filled, solvers must draw a line through 12 contiguous cells to loosely indicate the resting place of a thematic name ( a block of 15 cells, which must be highlighted ). Enumerations and word counts relate to grid entries. Chambers Dictionary  (2016 ) is recommended.)

[roslyn251254]

15a peEps

17 Call (ring up)

18 jetE (a leap)

25 ruLing

29 Scored

36 diVan (synonym for synod)

26 as onE

[roslyn251254]

5d noT

10 tOasted

30 theRe

your other answers are normal clues without a missing letter

the missing letters are 5,7  ...then 4,4,8

[Neveracrossword]

Matakari, I expect Roslyn's help was the final shove you needed to finish this off. 

I have good news for you. The latest Private Eye crossword is extremely Matakari-friendly!

[Matakari]

Greatly appreciated, Roslyn251254, this should be my final plea for help after which I should be on my own come what may! I have isolated the following answers which I think do not have missing letters:

13a ( Asps );  16a ( Tusche );  27a ( ZSA ZSA )

9d ( Uses Up )  ;  19d ( Lacerta );  24d ( Bonito )

Now, missing letters for the following?

1a ( Corks ) – modified answer;  14a ( Carroty );  31a ( Nitrian );  32 ( Neck ) – modified answer
34a ( At Peace );  4d ( Sirih );  7d ( Spraint );  22d ( Mazdean );  26d ( Coned )- modified answer 

[Neveracrossword]

Matakari, I think you have failed to read the preamble properly. You mention looking for missing letters in the modified answers! There aren't any -'in 28 other clues...'

14 'p (I)lus'

[Neveracrossword]

Matakari, not every other clue has a missing letter - as the preamble says, there are 28.... How many have you now ticked off?

[Matakari]

Thanks,NACW, I've now ticked off a sizeable number of letters that send me sailing through some rather rough seas!
MARIECELESEIVEMATCOONER
Looking to see where the other letters are, but I may not need them.

[Neveracrossword]

Thanks, Matakari. With Roslyn's very useful word/letter count, you will be able to make perfect sense of those letters (only a couple needed, and they're fairly obvious). Please, please do the final stage yourself! 

[Matakari]

Yes, this part does seem pretty obvious! A closer look at the remaining clues with  missing letters reveals what appears to be Marie Celeste and five mast schooner?

[Neveracrossword]

Matakari, I'm sure you're not really asking for further confirmation of the letters?  I'm sure too that you're very keen now to do something with the information - just do as the preamble says, indicate the resting place... and highlight a thematic name. This is the fun part of a thematic puzzle, pulling the theme together. It's up to you to spot the resting place, up to you to show you have the thematic name.