Thomas was the third son, and his eldest brother John was baptized in 1546, so 1550 seems a plausible guess for Thomas's birth year.
"...in the said writ, certify that by virtue of the aforesaid writ I went in my own person on the sixteenth day of May  ... to the tenements specified and contained in the said writ, with the appurtenances, in the presence of Rowland Hinde, gentleman and Thomas Machell, gentleman, named in the said writ, and thereto by me forewarned, and in the absence of Matthew Machell, also named in the said writ and thereto by me forewarned, by the oath of..."
Following is the text of the funeral certificate of Thomas Machell of Hackney, Middlesex, signed by his brother John "Mauchell."
FUNERAL CERTIFICATE OF THOMAS MACHELL OF HACKNEY, CO. MIDDLESEX, GENT.
Thomas Machell, Gentillman, died at his howse at Hackney the xxiiijth of June and was Buryed at the said parish church on Mondaye the 3rd of July 1581. He married Eme doughter of Anthony Tunsted [of Tunsted] in the County of Darby, and by her hathe issue fraunces his only son and heire being of the age of four monthes old or ther aboutes."
Have you taken a DNA test? If so, login to add it. If not, see our friends at Ancestry DNA.