Hi Martin,
There are a good few records about John.
He deposed as a witness in a court case of 1595 (Owen Shepparde vs Richard Riches alias Poynter) - TNA
Again deposed in a case of 1614 (Ann Riches alias Poynter vs Elizabeth Riches, her stepmother - TNA.
He is mentioned in his fathers will of 1558 (Thomas Riches of Yelverton - NRO), and in his uncles will of 1561 (Jeffery Riches of Yelverton).
The marriage of his brother Richard to Joan Underwood is partly explained in the 1595 court case, and she appears not to be a sister of John's wife, probably a cousin. The whole Underwood family is a bit of a mystery, partly due to having no early parish records for Kirby Bedon, but Alice's father is probably the James Underwood, gentleman of Bixley, who was under-steward of Framingham manor.
Most interestingly, to me at least, is that John's grandfather, another John, was killed in the final battle of Kett's Rebellion in 1549, as shown in the manor court for Framingham manor held the Monday in the Feast of the apostles Simon & Jude, 28th October 1549 (TNA). Several other manorial tenants were also among those killed, along with about 2-3,000 others, though very few names have survived. I have a very good article about the rebellion in which John gets a mention, which is how I found the court record. His manorial lands, about 46 acres, passed to his son Thomas. I have recently received copies of two other courts of the same manor, archived at Arundel Castle, which houses the records of the Howard family, the Dukes of Norfolk, and the lords of Framingham manor in those days. The then lord was in the Tower of London at the time of the rebellion, having fallen fowl of Henry VIII, who had only died a year or two prior. The other courts say from whom John got his lands, or part of them. I'm still trying to translate the Latin of those records, which is arduous!!, but fun. Send me a pm with an email address and we can talk further. I'll be interested to know your line of descent. Regards
Wayne