As a thought if you`re unable to make it landside at LHR, is see if there is an Indian grocery store when you`re home. I bought a brand called ``Tea India``, comes in a red and blue box and it tastes very close to M&S Extra Strong. The only place I can get it is to go out the neighbouhood where most people from India seem to live and there are a number of stores there that specialize only in goods from India.