Hi Paula
These are the two London apprenticeship records I found which may well refer to Richard (snr), the dates would be about right
1686 Dimock John, son of ..., Winslow, Buckinghamshire, maltster, to Richard Purchase, 23 Aug 1686, Woolmen's Company
1681 Hackney John, son of John, Wellingborough, Northamptonshire, woolwinder, to Richard Purchase, 25 Jun 1681, Woolmen's Company
DebbieG