The Indian example shown (Which to be fair, the OP does say he is not intending to use) is an example of a modular system where the required modules are assembled into a plate. Various similar modular systems exist for the UK market from which you could assemble the same configuration, i.e. a 1-gang plate with two holes fitted with a charger and a light switch, to make a UK-compliant assembly. Although, I would think the USB cable would be an annoyance every time you use the switch, and might readily get damaged.
However there is a major caveat as mentioned above, that many light switch positions have only the line and switched line conductors available, not a neutral which the charger will need. It would require rewiring back to the light fitting or associated rose or junction box, with 3-core + earth cable, defeating the idea of using the extant switch wiring.
Finally if you are lucky and do have a neutral available at the switch, and make up a suitable grid assembly, you will probably find it necessary to chase out the wall and install a deeper box, as standard light switch boxes are too shallow for a typical charger module.
