SDM, the Life Skills B1 for anyone that has a reasonable amount of english is pretty easy, I am friends with someone who took the Life Skills here in the UK back in May of this year, basically it consists of holding a short conversation in english, usually with another candidate if available, whilst the examiner listens, it really is pretty easy, and the beuty of it is once gained that B1 is usable in future years for Citizenship, ILR etc,etc.
Good luck, and it may be worth considering trying to change to a B1, especially if your fiancee can hold a decent conversation in English, what my friend did find was the organisation of the company (Branch in Portsmouth) left a lot to be desired, firstly they asked her if she could take the test in London (she lives in Bournemouth) though they have a Portsmouth branch, she insisted on Portsmouth, when she got there they accepted her passport photo prior to taking the test, 1 week later they wrote saying the photo was not acceptable, they could not issue her documents until she provided other ID, and could she attend the Branch in person with different Id, several phone calls later they decided that the original passport and photo were acceptable, and she received her B1 certificate, I do sometimes wonder how some of these companies that seem incompetant at the very least manage to get this approved status, maybe its the old case of not what you know, but who you know.