Hey there! I noticed you did the casual Loki look, would you be able to create the Loki costume with items available in the uk? Thankyou!
Creating a screen accurate female Loki costume will not be easy nor inexpensive. Each piece is going to have to either be completely hand constructed or seriously modified.We've been asked about a female Loki costume before, and our posted answer can be found here.
We really do apologise, but unless you already have a pattern started for his costume we can't be of much help. We can supply you with a few links to tutorials on how to make some of the pieces accompanied by reference photos.
Fortunately, someone has been kind enough to upload a tutorial on how to make your own helmet out of light and inexpensive materials to deviantart (found here).
We found a lovely Tumblr user by the name of kidofmischief who is currently constructing her own fem Loki costume from scratch. We highly recommend taking a look at her process and seeing what you can take from that.
We really do wish we could be more help, and if you have any technical questions about this cosplay once you get a pattern started we'd be more than happy to offer you any advice.