I have an R-tech tig 160, it's a good machine and the back up is excellent, but more than your budget, also they have increased in price recently so a 200a AC/DCis £1400, so are not cheap anymore
You are taking a big chance with buying a machine from China as the warranty is useless, buy only from Europe.
My personal recommendation would be if I wanted a decent setup is this....http://www.ebay.co.uk/itm/Stealth-DI...YAAOSwAuZX4laC.

As already said by Jazz, learning tig takes a long time and if you want to stack dimes like a pro in all posistion, it takes years to learn and with all due respect to the guys on here, you will need to join a welding forum, from personal experience I can fully recommend this site..http://www.mig-welding.co.uk.

Martin