HI,
You will not be liable for stamp duty as you are not buying the house, only transferring full ownership to you, so you retain your first time buyer status.
you will get full mortgage interest relief at source for a single person (ie, 10K @ 20%)
use same solicitor as cheaper on you both - should only take 4 weeks to transfer full ownership
The banks will take into consideration that you have already been paying mortgage (half of it) regularly for 2 years and may therefore be willing to let you take on mortgage. But this is a high mortgage for a single person - crunch your figures very carefully and stress test to an additional 1%.. - don't forget you will have to finance buying her out & solicitor fees..