There is a Peter Markoe Spanishtown (Virgin Gorda?) 5 oct 1727 signing letter with others on death of King George.
Also a petition to Governor Hamilton of the British Leeward Islands requesting permission to remove to St. Croix. Petition begins "Petition of the poor inhabitants of Tortola and Spanish Town to Governor Hamilton. Whereas the Island of Tortola is patented by six or seven persons being granted by former generals, the poor inhabitants having no land to live upon but sufferance ... your Excellency's humble petitioners desire the humble liberty of settling upon the Island of St Croose [sic] as subjects of Great Britain and shall ever remain, and defend the said Island against all manner of foreign Princes and maintain the said Island in HM name etc. Signed: Charles Darcy, Joseph Hall, Peter Markoe ...."
Walter Hamilton was Gov of the Leeward Islands 1710-1711 and 1714-1721 so this puts Peter there as early as 1710 and as late as 1721 (actually, Peter was still there 1727 when he signed the condolence letter. This was six months or so after Capt Abraham was born). St. Croix was "abandoned" by the French between 1695-1733 so I don't know by what authority a Brit would be allowed to move there. As squatters?
Spanish Town, Virgin Gorda, was capitol of the Leeward Islands until about 1747 when it was moved to Tortola. It is most likely the "Spantons" Calmeijer mentions in the St. Eustatius Markoe records.