I put an order in with a polish company called army world for regular Flecktarn, They also stock Tropitarn.
Sizes are done as the Germans do them, So everything is metric. The very largest stuff might just fit, There is a size guide on there somewhere but the sizes are set out like:
Nr.20-1 185-190/120-130
185-190 (height) 120-130 (gut/chest) Nr.20-1 (standardised code for easy ordering).
They have stock of new and Mil surplus. The site is a pain to navigate but this link sends you to all of the Bundeswehr gear in a single 20 page list.
http://armyworld.pl/firm-eng-1142347122-Kontrakt-dla-Bundeswehr.html
You'll have to click through the pages to find what you want off that link, but it will be faster than searching for individual items.
5 zloty to the pound atm.
Highlights for you.
Trousers, 55Zl (£11)
http://armyworld.pl/product-eng-22-Desert-TrousersTropentarn-Wustentarn-Military-Bundeswehr-Original-Demobil-SecondHand.html
Shirt 25Zl (£5)
http://armyworld.pl/product-eng-23-Desert-Shirt-Tropentarn-Wustentarn-Military-Bundeswehr-Original-Demobil-SecondHand.html
Boonie 28Zl (£5.60)
http://armyworld.pl/product-eng-91-Military-Desert-Hat-Bundeswehr-Tropentarn-Wustentarn-Original-Demobil.html
Webbing 39Zl (£7.80)
http://armyworld.pl/product-eng-24-Tactical-Instrumentation-Bundeswehr-5-pieces-Flecktarn-Original-Demobil-SecondHand.html
I put an order in with them a few months ago. I think it was £50 of gear and the shipping made it £70. The shipping is the real killer from that site, but it's still cheaper and has a better range of sizes after the shipping! The shipping is untracked and takes about 14 days.
Also look at the G3 mag pouches and the regular Flecktarn gear.
G3 pouch 5Zl (£1).
http://armyworld.pl/product-eng-137-Military-Cartridge-Pouch-G3-Bundeswehr-Flecktarn-Original-Used.html
Picking up a few of those will cover the shipping alone if you base the price on what the UK surplus stores want for them!