Yes they need a certain amount of info before you can even make an appointment so they can rule out conflict of interest or work out if they would have a capacity or be a fit for the case
My experience is they normally review the broad nature of the query and get back with a "yes, we could take this on, an initial consult to advise on options etc is 400 for the hour" or "no, we don't have capacity, try ms/mr X instead". In both cases you get a response so you know where you stand which is just basic good business imo