"I work in the City as does my French partner: the European bankers, lawyers and asset managers are all talking about how London has changed for them now and are thinking it may be time to head home."
A Marxist may very well say that these people have taken advantage of an extraordinary situation whereby enormous capital flows have been allowed to free cross national borders without impunity to the detriment of workers outside the capitalist class.
In short, these people are the ones that have got fat off the cream of an almost anarcho-capitalist paradigm, and now that paradigm is changing. Considering that the paradigm lead to a scenario where profits were privatised and losses socialised, that Marxist may very well just say these people were a bunch of exploitative parasites on the back of European workers and those parasites are now upset that the party has ended.
I'm not a Marxist, but sometimes looking at situations from that perspective is rather interesting.
But I will say that London does not exist for the benefit and lifestyle riches of a transient global capitalist class. It is the capital of Britain, not a Monaco on the Thames.
Did it ever occur to any of these people that the thousands of British Londoners, many who have been driven out of the capital by the high cost of living, may have spent the last twenty years distressed at how their London was changing? Supercars racing down streets outside their homes, their quirky markets turned into corporate money pits, their areas gentrified into soulless wastelands of glass where hundreds of new build apartments stay dark night after night and are nothing more than a place for the global wealthy to park their money? Or their homes compulsory purchased from under their feet and the new development marketed to investors in the Far East?