Can I get a VAT refund customs stamp within the secured side of Terminal 5? I am arriving Terminal 3 on BA and transferring to a Terminal 5 flight to NYC also on BA. I would prefer to make the terminal transfer by bus without having to go through customs into the country. Based on the terminal map, it seems like the only customs office is outside security. Thanks.

http://www.heathrowairport.com/stati...row_T5_Map.pdf