Possible Clues:

• One turned up clutching £25 for Tom Jones?
• Sandwich, for example, set me back around £25!
• This writer's emphatic refusal to withdraw title character
• Author's negative response is reflected in titular character
• The seventh earl of Cardigan, for the word "cardigan"
• Ohm, for one
• One nominally involved? Gosh, no, the reverse of that
• Person for whom a thing is named
• Sousaphone, e.g.
• Alison Bechdel, for the Bechdel test