Hi Joanne, I have recently found my Richardson ancestors from St Giles parish (Bloomsbury):
George R (b.abt1805) m Catherine Sullivan (b.Cork, Irl):
children: George Wm R (b.1835) m Charlotte Emma Escudier;
Catherine R (b.1837); Frederick R (b.1839) - all born St Giles
Even if you see no link to yours at least you can eliminate them from further enquiries (!)
Good luck - early 19thC Richardson genealogy in Middlesex/London is very tough work - Jeremy