Answer: SETINSTONE
The answer SETINSTONE has 17 possible clues. See the results below.
Possible Clues:
- Well fixed
- Some games of short tennis arranged and unlikely to be changed
- Light metal and sulphur found in deposit and bones at the centre of Excalibur, presumably
- Extremely hard to change
- Impossible to change, or like 17-, 20-, 39- and 56-Across?
- Impossible to change
- "Avoid saying, 'Nothing is ___' ..."