Hi just completed this on my xbox but is has not given me the achievement! Is this because I sold Tonila my rubbish guild armour straight away as my steel armour was better, and now the game is glitched three weeks later in my life!!!!!!
Anyhow is there any way of obtaining the guild armour back so I can get my master guild armour? And then get my cheevo!

Either you have to buy it back from the merchant you sold it too.... or start over.... but it's not all about the achievments..... right??

You cannot buy it back off Tonila, Bethesda needs to fix this as after two months playing I am now getting done. Yes I play single player games for cheevos. Skyrim is good but I do not want to re play two months of it to get a single mission done! Its good but not that good!

This has been an ongoing issue for some time now. If you have PC you can add it via the console, other than that SOL I believe. :\

How do I do this ?

Should be:

player.additem 000D3AC2 1 (Thieves' Guild Boots)
player.additem 000D3AC3 1 (Thieves' Guild Armor)
player.additem 000D3AC4 1 (Thieves' Guild Gloves)
player.additem 000D3AC5 1 (Thieves' Guild Hood)


Note: Never had to do this myself, not saying 100% it will work, but i know that many others have had to do this.

Actually, you don't have to replay the whole game. Just start a new character and finish the TG questline. The questline is pathetically short, it shouldn't take more than a few hours. The achievements are universal for all characters.