I have no connection with the Perreau family except in a former capacity as a researcher. Loking at the the forum page I see no mention of Robert George Perreau b.29-12-1786 at Calcutta and Lee Sindrom as the founders of the Singapore line of Perreau's. Perhaps you may already know this.
Re: John the tailor of St Andrews Holborn.It is likely that he was connected to Robert Breton but despite living in London a few years back and looking into all records was unable to prove a connection has anyone out there found it?
The Twins were involved in espionage in the 1770's during the tensions with France and Spain. Records at various locations including admiralty papers prove this.
I am now retired, most of my papers are at the SoG in London.