Onitsuka Tiger Tai Chi trainers

I have tried some Onitsuka Tiger Tai Chi trainers, but the size UK 11 (which I am in Vans) didn't fit, so I went for the 12s, but there's like an inch of space at the toe - they'll get all stretched when I use them, so I'm still not convinced about these. The great thing with Schuh is that they do refunds up to 1 year from the date of purchase.