Captain Thomas Sandford's Company of Firelocks
"Behold the messenger of death, Sanford and his firelocks, who neither use to give, nor take quarter"
You will often see the wargamer fact™ that the Regiments raised to fight in Ireland all wore green or yellow coats. This is slightly problematical as very few coat colours were recorded (there's a handful of red coated regiments, one in either red or grey, one green, and a couple of yellow coated regiments), what was recorded about the clothing issued were mostly complaints about the poor quality of the clothing, for example:
"the cloth is very bad, the suits ill and slightly made up, the cassocks not lined, the linings of the breeches not very good cloth, the caps so little as they cannot be useful..."
in J. Hogan Letters and Papers Relating to the Irish Rebellion 1642-1646
Upon their return from Ireland soldiers were given clothing: Orlando Bridgeman, the Governor of Chester sent requests to neighbouring towns and counties for clothing and shoes for the returning troops. So desperate was the condition of these soldiers that this is mostly believed to be civilian clothing, not standard coloured coats for individual regiments.
The Osprey Elite, "Soldiers of the English Civil War (1), Infantry" illustrates one of their number wearing a green coat, the plate description gives "...wearing the new coat issued on his arrival in England". I have seen this illustration used as definitive evidence that Sandford's wore green coats. Sorry - coat colour is pure supposition, we don't even know for certain if they were even issued with coats.
* in case you're wondering, it's pronounced 'harden'