Year on year sales for the second quarter are up by 53 per cent, and for the first half by 60 per cent.
However UK sales rose by only one per cent in the second quarter and eight per cent in the first half.
The international sales growth was affected by the opening of three new websites in Australia, Spain and Italy.
Chief Executive Nick Robertson described the figures as a strong first half performance.
He said: “With costs and stock tightly managed and retail margin ahead of prior year, we are confident of achieving results in line with market expectations."