Did you not do any research before applying? Surely if you had done due diligence you would have found the huge long thread in the interviews and sponsorship forum about the Qatar MPL and it's merits or lack thereof. You will be working in Doha IF you get onto the course, pay over £100,000 AND complete it to the standard Qatar require.
No-one can give you any real insight into working for Qatar Airways off the CTC MPL as none of them have started line training yet.
My advice - Do some serious research before spending the money on attending selection. Reading the Qatar MPL thread would be a good start. IF you do decide to go along to selection, make a list of questions to ask, don't fall for the marketing hype and show some initiative/intuition in the interview and group exercises. There are plenty of other ways into commercial flying.