Currently there seem to be two groups:
The Brexit Light group who want to preserve access to the single market with hopefully some concessions on free movements.
And the Hard Brexit group who see controlling migration as the most important thing even at the cost of losing access to the single market.
Whatever happens there is going to be a long period of uncertainty which could last for 5-10 years. Only once the dust has settled will we know what impact there has been on the economy and country.
Companies are going to be less likely to invest in the UK, before Brexit it was a logical choice to open offices in London, now it is not so clear cut.
It is also less likely that talented people from across Europe will be tempted to move to London. Pre Brexit the UK (in particular London) has been a very attractive place for highly skilled people, post Brexit those people are likely to choose a different capital city to call home.
My feeling is that Brexit will be very bad for London in the short to medium term.