It looks like most of us will not attend Sheffield.
I know I will, some others are still undecided or did not decide how yet.
Personally, I think I will leave Paris on Thursday and come back on Sunday evening.
About the worlds pack, it was possible (either by giving a player's name who will take it for you, or even by doing a grouped command with another player). However, it appears that those packs could only be pre-ordered until yesterday and are no where to be found on the alderac store.
If (maybe...) they brought too much packs in Sheffields and decide to sell those on site, I should be able to pick you one, but I cannot make any promise.