Global Airport Cities says Martin Speed is the new tenant at warehouse facility near Heathrow:

The 35,334 sqft Unit 163 has been let on a 10-year lease with an option to purchase. Located less than two miles from M4 Junction 3 and 2.5 miles from the Heathrow Cargo Centre, the unit is one of two industrial/distribution warehouse units on the 2.5 acre site.

Art Dealer Moves to Heathrow (GlobalAirportCities)