The article gives only partial figures: "Implants were given to 56 girls aged 12 or younger, with 281 cases involving girls of 13, the figures show.
More than 3,000 cases involved girls of 14, with 6,000 implants given to 15-year-olds, disclosures from 61 of 160 NHS trusts show."
And also specifically mentions LDs, and one Health Authority is quoted as saying they are only provided after close consultation including with the Safeguarding Team.
Given the small numbers it could be (and I really hope it is) only the sort of cases that NotCitrus mentions, or the difficulties of maintaining 24/7 supervision in residential homes (for if the boy also has LDs, there may be no hope of a properly used condom and you really can't vasectomise at that age).