see Poland Street 19 to 44 in London Addresses dataset
Mark Martin 41 (or 42) Poland St ratebooks 1792-3 Le Grange & Martin 1793 / Mark Martin ratebooks South Molton St, St Geo Han Sq from 1795 / Sophy Hellen bapt 13.6.1802 & Elizabeth Sarah bapt 14.4.1805 St Geo Han Sq of Mark & Mary Martin / SunFire 1810 Mark Martin staymaker 17 Southmolton St / Marc Joseph Martin age 73 from South Molton St bur St Geo Han Sq 1831 / will PCC 1831 Marc Joseph Martin St Geo Han Sq / Morning Post 21.12.1833 ad for claims on Marc Joseph Martin deceased stay and corset maker. I could find no information about Peter La Grange, perhaps his partner, but who remained in the Poland St ratebooks till 1800