In the 1980s and 1990s, attempts were made by gay rights organizations to equalize the age of consent for heterosexuals and homosexuals, as the age of consent for homosexuals was set at 21, while the age of consent for heterosexuals was 16...However, the July 1, 1997 decision in the case Sutherland v. United Kingdom resulted in the Sexual Offences (Amendment) Act 2000 which further reduced it to 16... Today, the universal age of consent is 16 in England, Scotland, and Wales.
So yeah at the time I wrote this fic (2006), the sex between them was legal.
Im glad you liked the fic. It was the first time I ever did a Remus-orientated fic that didnt involve Remus/Sirius (even my Remus/Fenrir fic had references to Remus/Sirius) :-)