Hi Vishal,
My advice to you is to focus your initial research on the schools themselves... for example, class profiles are generally available on each program's website-- that will tell you about the students of these programs. If you cannot locate them, get in touch with the Admissions offices and ask. You should also be able to view employment statistics at each which is very important, and things like average GMAT etc.
With regard to job prospects in the UK and visa opportunities etc, again first have a look at the employment stats, but also reach out to the Admissions and Career Services offices at each school and just ask these q's... they are best positioned to tell you exactly how many international students stayed in the UK last year for example, and what types of jobs or visas they obtained etc.
While I personally lived and worked in the UK for 4 years and did my own MBA there, I still feel the answers you are looking for will be found at each individual school, and it's appropriate to reach out and ask these q's to the schools for better insight.
Side note I'm not sure what you mean by not using the GMAT; perhaps that you will re-take?
Good luck to you!