In the spirit of London Fashion Week, Heathrow is offering extra points for fashion purchases made at their duty/tax free shops until 16 October. The offer varies on spend levels:

500 points when you spend £125.00-£199.99
1,000 points when you spend £200.00-£299.99
1,500 points when you spend £300.00-£399.99
2,000 points when you spend £400.00 or more
Valid from 16 September to 31 October 2016.

Unhelpfully they have not posted the detailed terms and conditions making it hard to know which stores are included. For example, some stores have clothing as part of a wider range of items so it is not clear whether these will be included to earn the bonus points.