Strictly she should have asked permission from the artist and she should have credited her
Nope, she did not need a copyright license to make a copy for private use. No copyright infringement happened IAW the Copyright Designs and Patents Act 1988:
“107 Criminal liability for making or dealing with infringing articles, &c
(1) A person commits an offence who, without the licence of the copyright owner--
(a) makes for sale or hire, or
(b) imports into the United Kingdom otherwise than for his private and domestic use, or
(c) possesses in the course of a business with a view to committing any act infringing the copyright, or
(d) in the course of a business--
i) sells or lets for hire, or
ii)offers or exposes for sale or hire, or
iii) exhibits in public, or
iv) distributes, or
(e) affect prejudicially the owner of the copyright, distributes otherwise than in the course of a business to such an extent as to an article which is, and which he knows or has reason to believe is, an infringing copy of a copyright work.
(2) A person commits an offence who--
(a) makes an article specifically designed or adapted for making copies of a particular copyright work, or
(b) has such an article in his possession,
knowing or having reason to believe that it is to be used to make infringing copies for sale or hire or for use in the course of a business.
(2A) A person (“P”) who infringes copyright in a work by communicating the work to the public commits an offence if P—
(a) knows or has reason to believe that P is infringing copyright in the work, and (b) either—
(i) intends to make a gain for P or another person, or
(ii) knows or has reason to believe that communicating the work to the public will cause loss to the owner of the copyright, or will expose the owner of the copyright to a risk of loss.
(2B)For the purposes of subsection (2A)— (a) “gain” and “loss”—
(i) extend only to gain or loss in money, and
(ii) include any such gain or loss whether temporary or permanent, and
(b) “loss” includes a loss by not getting what one might get.