Hi,
you don't actually need the 2nd NL. There isn't anything in there that wasn't in the first letter or that KCC and the embassy you are having the interview at can't email you.
Our 2nd NL took 6 weeks to arrive (our interview is in May aswell) so we emailed KCC and the embassy. KCC confirmed interview date.
the embassy emailed through details on getting the medicals and police check done, and the list of documents needed for the interview.
They also said to print out the email and take to the interview as confirmation of your appointment.
Don't stress, email or phone the embassy your interview is at and they will give you everything you need.
