By Andy Silvester Much like watching somebody stand too close to the edge of a rooftop can bring on the heebie-jeebies, the City’s institutions giving a guarded welcome to more crypto-backed vehicles can also leave an observer a little nervy. It is not that long ago that we were in the ‘crypto winter,’ watching token prices crash and seeing some very well known individuals banged up for 110-year stretches. With Bitcoin at a record high and the Stock Exchange putting the welcome mat out to exchange-traded notes, all of that seems forgotten. There is nothing inherently wrong with cryptocurrencie…