The shirt is ripstop MTP, PCS cut but a lot of different features. No pockets but Velcro fasteners to the back. The zip is waterproof and the inside of the jacket has a storm flap (I don't know what they are called). The arms have inserts for pads ( like the new MTP aircrew door gunners trousers).
The chap I got this beaut from didn't know if it was unit made or a trial shirt. Very well made, I don't think commercially MTP material is available to buy yet and I think the MOD is still strict with it, albeit some company's have produced very similar patterns - I could be wrong though!