Let's compare ease of refund in various countries:

U.K. (LHR 4) - get forms endorsed and refunded (in GBP) after security - never had them look at the goods (what do you do with stuff that you have to check-in?).

Germany (FRA 2) - get the stuff looked at by customs after check-in (bags get accompanied to the post). Get refund in native currency after security/passport control.