I am a UK citizen currently in US. I need a UK mailing address for some "official" documents. NHS/EHIC card, etc. (No illegal activities.) I will supply FedEx prepaid labels and supplies and arrange for pick up for forwarding. I can provide a similar service going the opposite direction or receive delivery of purchases (many outdoor brands) that can not be shipped abroad by US retailers.
If you know of any official services in the UK that do this, please let me know!