hi Uday,
You already done a MBA.Why you want to do it again?.I agree that there is some quality variations but wont you be bored in studying same papers ?.If you think UK as your work destiny, you can get the same HSMP visa with your present PG degree..rather than investing again.
It is true that some people in UK who had done their Full time MBA program go for Exe.MBA program again....But the story differs with your case..
If you are not satisfied with my reply, then
1.UK universities agree without IELTS provided your mode of studying during school and college should be English.
2. If you are not too specific on accreditations like AMBA etc then you can pursue for LSBF...I think your IIPM-MBA and LSBF MBA are equal...
3.No idea on LSC and Cardiff.