I don't know whether it still holds true but a few years ago it was reckoned that a lot of Manchester - India traffic routed with LH.
Even if all the 10,000 pax via Dubai were all Mumbai and excluded Mauritius, it's less than 200 per week or 30 a day or 5 per flight if it includes outbounds and inbounds. Do QR & EY have a good service to India? The other suggestion I recall is that Delhi would be a better destination from MAN, but is that the case?
Still, from the comments made on forums, it would be easy to assume that the percentage of pax going just to Dubai was a lot less than 30% and that the vast majority were simply using it as a hub.
As regards Bangkok, at one time it was said by Emirates to be the most popular onward destination from MAN. Again, whether that is still the position, I've no idea.