A couple of observations.
The interview is - to say the least - anodyne. It contains nothing about "British India" that has not already been openly discussed elsewhere. (There was a programme, for instance, a couple of weeks ago on BBC 4 - British History's Biggest Fibs devoted to the fabrications of Victorian politicians about Britain's behaviour in India).
Contrary to your understanding, we are not currently living in post Brexit Britain. Britain is still a full member of the EU and has not yet even made its application to leave the EU. One point that Mr Tharoor does make is the investment by Indian companies in Britain and the possibility of some relocating, possibly, to Ireland. I think the interview would have been more interesting if he had developed this possibility.
The interview - to me - just seemed to lack any teeth. it was clearly recorded and edited (possibly even "scripted" before transmission. As I said earlier, anodyne, clearly intended to no offence to anyone.