Applying to LSE

Hello guys, I have just finished year 13 and have achieved A*A*AA in Maths, Further Maths, Physics and Comp sci. I have chosen to do a leavers programme at a big finance company for a year in London instead of going to university as I realised I do not want to move out of London ( I got an offer from Warwick for Econ). During this gap year I want to apply for unis such as LSE and UCL with my achieved grades. At LSE I want to study the Bsc Maths, Stats and Business or Bsc Financial mathematics and statistics. For both of these courses the TMUA is not required, I dont think I will have time to study for the TMUA whilst at the leavers programme since it is full time. What are my chances of getting an offer, should I still attempt the TMUA despite not having the proper time to devote to it.