Having been an expat and having friends who have become expats, I have a few comments that may be useful for you.

Being an expat is probably more expensive than you think. Even if there are tax advantages there may be hidden "taxes" (e.g. high rents in expat housing, high grocery bills for home comforts, flights home etc...).

Accordingly I always offer my friends and associates this advice:

i) never accept any pre-tax salary lower than your pre-tax salary in the UK, even if the after-tax salary is higher

ii) budget for at least three or four business class returns to the UK per year in addition to your salary

iii) find out the rents on expat housing (including service charges) before negotiating your package and demand a package that will pay for high quality accommodation with facilities (e.g. private gardens, pool etc...)

iv) in some parts of the world motor cars can be much more expensive than the UK due to high taxes and I understand that this is the case in India, at least for imported cars - accordingly you should build this into your budgeting and package and if possible I would take a company car rather than buying your own.

v) if you have children, ensure that your package will pay for their education at a high quality school, preferably a boarding school in the UK (if they are the right age)

If you cannot achieve the above, you may be better off staying in the UK.

Hope that helps!