Guys! I used to live just up the road from East Ham (Manor Park) --- you're making me
homesick!
But you've also said everything I could possibly say, just about.
Canary Wharf (someone had, I think, the confusion) is not "The City" --- that is a specific area where all the old financial stuff is/was, around Aldgate, Tower, Bank. It is also
actually The City of London, with its own corporation, and boundary markers on the main roads.
Canary Wharf is the new development on what used to be a big part of London's docks --- a wharf is another name for a pier, for a ship to dock alongside. It is very modern. (or it was when I last saw it...).
The main transport link into and out of Canary Wharf is the
Docklands Light Railway --- check out the Transport For London site.
If you want to live in the Canary Wharf or Docklands area, then you had better have a
really good job! That would be very expensive. and Posh. Invite us over! Otherwise, checking the rail maps will help to see what's connected.
I'm ashamed to say that there are are areas where you might feel threatened, my mother country does have its rough and racist elements, and never wave your money or your smart mobile phone around! So yes, some of the warnings given in this thread you can take to heart. On the positive side, you will never have to bribe a policeman or official (in fact you'll be in big trouble if you try).
It is a good idea to be able to speak Tamil or Malayalam in East Ham

(nearby Green Street is probably more Northern Indian) --- but I got by there without almost as well as I do in Chennai! Even including teaching the basics of mridangam to young Malayalee kids!
If you want Indian culture while you are there, there is heaps. My thing was Southern/Tamil, but it is all there: temples, mosques --- my wife used to go to a Tamil church just down the road from where my house was when I took her there to visit. Music, films... The Nehru Centre and Bharatya Vidya Bhavan are good centres for classical stuff; meeting up with the Sri Lankan community at any if the Tamil temples will get you informed about the Carnatic classical scene.
Vegetarianism is pretty well understood, and won't be a problem, although, of course, our English food is pretty bland to the Indian tongue; Mrs G used to put a peppercorn in her mouth, or take a bite of a chilly while eating, just to give some flavour. Southern Indian food (mostly Sri Lankan) is one of the cheapest ways of eating out; pre-packed stuff from supermarkets is expensive.
I have no idea about rents, as I owned my little house there for past twenty years (wish I still did). I'd probably be shocked, and wish even more that I still owned the house.
Owning and running a car is very expensive, and you'll probably be fine, certainly for work days, with the public transport which is pretty comprehensive. Buy the longest period season ticket you can, once you find a place where you think you will stay (the tickets work in zones, so even this has some flexibility).
But, why not take an International Driving Permit and your Indian licence with you. You never know, you might get the chance to drive, or maybe hire a car for a weekend or something. Be warned: every little thing you do wrong is likely to be caught by some damned automatic camera, resulting in a stiff fine arriving on the doorstep.
What do you people who work abroad do about banking? Maybe your employer will recommend you to the bank they use (they will want to pay your salary into a bank account), or maybe you could check out one of the Indian banks that has London branches (errr... HSBC is pretty international, ICICI, CitiBank have branches, probably more).
Work culture? Arrive early, leave late, dress smart (suit and tie), but you probably won't have to call anyone 'Sir'. I never did manage that 'arrive early' bit...
Working social life tends to based around bars and pubs. If that isn't your thing (and its not mine) then you might be seen as a bit stand-offish, but (if applicable) best just to tell that you don't drink. Go along once or twice to meet the guys. It is
very variable: some places have a work-together/play-together culture; others have no social side at all.
I hope my few thoughts are useful; I think others have given as good as practical info as I have. I haven't worked in London since 2003; I haven't had a home there since 2005.
Oh... it's cold. Except for a couple of weeks a year when it can be as hot as Chennai. Those weeks usually happen
sometime between about April and October, but are quite unpredictable!