Azed

[JJ109]

I am totally lost with which letters to enter, can someone help please?

12d Slaty stone, nicest when replaced after unsightly clash (10)

The answer is ten letters and will be SCHALSTEIN (slaty stone) and an anagram of "clash" and "nicest" (minus the c)
The instructions require me to add that extra C somewhere in the answer, making a nonsense answer of 11 letters but which conforms to the wordplay. Where do I add the C, please?

[dannyk13]

Between the 'e' && 'i' ?

[iminoz]

It fits between the E and I

[JJ109]

Thankyou - but I must be thick - why there?
I understand that the first 5 letters have to be SCHAL ("after clash") but what states that the C doesn't go after the L or the S or T etc etc?
Is it just that you have solved the other clues and know that it has to be where you state? Or is there something in the instructions to advise?
I do not like this AZED today!

[iminoz]

I had the crossers for 26a and 33a, and the preamble says, for down clues, the extra letter will not be in an unchecked light.
I agree, that aspect of it seems too arbitrary.

[JJ109]

Thanks Both Danny and Iminoz - I also had the I at 33a, but I might give up on this one. I can understand the across clues instructions but I don't like not knowing where to insert the extra letters in the down clues. Thanks to both for your help

[Spoffy]

If it helps, the only entries where the position of the extra letter is not clear from the wordplay are 4d and 12d.

[JJ109]

Thanks spoffy - that is reassuring - might have another go at it tomorrow, when my head clears a bit. I have to admit that the few other down clues that I have solved, did not give me a problem with the extra letters

[Spoffy]

In 4d the extra letter is in position 2.

[JJ109]

Thanks