Hello Tej,
Although Lancaster is 22nd in FT ranking but from my experience of talking to previous MBA students from Judge, Oxford etc i have figured out that Warwick is more known than Lancaster. Although Lancaster has very good research facility and fee is also less than Warwick although not very much though.
But Lancaster is little far from London so if you have to go for a single day trip it will be hectic.
It depends what you are looking in MBA because as you would have found till now that no school in UK will guarantee Job . I have been to Lancaster and i will say that Warwick is more picturious