Here's an article from 2012 which quotes Margaret Griffiths of Mermaids.
www.huffingtonpost.co.uk/2012/01/23/nhs-puberty-delay-drugs-children-gender-identity-disorder_n_1223166.html
Until now, under-16s in Britain seeking treatment for Gender Identity Disorder had the choice of going overseas or waiting until the age of 16 to proceed with gender reassignment surgery.
In the past decade the hormone-blocking drugs have been used increasingly in countries such as the US and the Netherlands.
Margaret Griffiths, liaison officer for Mermaids, a charity that offers support to families and children affected by GIS, also supports the drug trials.
“Most children with GID have suffered for as long as they can remember. But previously they could only seek treatment at 16. By this point boys have already developed facial hair and a deep voice and girls have grown breasts," she told The Huffington Post.
Bernard Reed of GIRES is also quoted in this article: “We have been campaigning since 2005 to bring Britain in line with other countries, such as Belgium and Canada, by offering children the opportunity to suspend the process of puberty while they make a decision.”
So perhaps Griffiths's child was 16 or over when treated by GIDS with puberty blockers, not 14 as implied by the 1997 Sunday Times article, so although that article starts with the headline "Children of 14 get sex change treatment on NHS", it doesn't actually say that any child under 16 had been given puberty blockers on the NHS.