I think these 'letters' are completely made up.
You know how you get 'professional compers' - people who manage to make money by entering lots of competitions? I think you get people who make a bit of pocket money by writing these 'true life misery' open letters.
You have to laugh at the Guardian's supposedly classy take on the whole 'my baby was born inside-out' genre, though. It reads like a pastiche of a Joanna Trollope novel crossed with mills and Boone. Joanna Trollope would be far more cutting, though.
Bloody Guardian, with it's patronising idea of 'what the ladeeez are like.'