Its hard to find in england with out postal order...
But if your not entirely fussed a few normal trainers that are very nice and that you can box in..
Are the flat soled henry lloyd trainers, Many nice puma trainers..And the addidas goodyear ones..
Theres something in the aiba rules that your shoes shouldnt have a heel etc etc..And if you get too sick of looking for some nice boots..I know those are pretty good for boxing..
Peace