Just a quick review for Silverman's as this was the last of stock.
Really great in contact when queried about the dimensions and measurements of said piece, pleasant and professsion. Took a punt and the parka/jacket is great! Fit as expected and compared to a Flecktarn field jacket (This being the Mountain Infantry Parka Gebirgsjägerparka I know its kinda supposed to fit over all other gear usually, but for me I'm treating it like a solid colour take on the above) I think is a 50/50 cotton/synthetic blend, maybe 35/65, definitely a little more water resistant as-stock. The hood is a little bigger overall and the press studs/buttons are placed differently (studs on cuffs, buttons on chest pockets) but I'm a dab hand with the sewing machine so I'll be making minor revision to have the hood/storm flap fit that little more perfect.
I'd wholly recommend Silvermans as a seller, top service all round, delivery was speedy too. Cheers! :D