I've had a few of these, never ceases to amaze me how shit the letters are!
Taking the piss for a bit is quite amusing with a few replies making it sound like you've actually fallen for it, the thing is it MUST work before they keep doing it. Last time I actually offered them money if it would help to "expidite" the process, they were understandably quite pleased by my offer.
p.s also using the name "Mary Hinge"