I did it! 1 month after setting my mind to it I have a pretty decent uniform put together 
I was pretty lucky finding a flightsuit that fit for a bargain price on eBay. I did however run into some problems along the way.
I foolishly bought black kneepads instead of white, so instead of dyeing them I had to use a mixture of primer and acrylic paint to get them grey.
I found an OD belt, tried bleaching it and dying it grey and this failed quite spectacularly, it ended up a light greeny grey with tons of rust everywhere! I do not recommend this one bit, lol.
The white belt tinted a great light grey using RIT pearl grey, but did suffer some light rusting on the fabric. I had used a little clear nail polish on all the metal parts before dying to try and minimise rusting and whilst they all still look rust-free, the inside parts must have leaked some rust into the fabric. Very annoying, but not too severe.
I bought the rubber leg hose connector from Nickatron, looks great! I dyed the leg hose (which is a fishtank gravel hose) using yellow glass paint. Made a mess of my sink, but some acetone nail polish cleared that away quite easily and it only too 5 minutes to dye.
Prop-wise, I’ve ordered a few parts and am planning on building the bulk out of styrene. Any recommendations on what thickness to use for the main bulk of the shell?