This is the information I've found:
"Candidates for the partnership awards or those undertaking projects at fee-waiver institutions will pay no tuition fees and will be given a stipend from the Fulbright Commission for international travel and living costs. Stipends will be £12,000 for locations outside of Greater London, or £13,500 within London."
From what I can deduce, that means a portion of the stipend must be dedicated to travel arrangements.
Same as this, from the 2013-14 handbook:
Fulbright Grants generally provide round-trip transportation, language or orientation courses (when appropriate),
a book allowance, maintenance for the academic year based on living costs in the host country, a nominal
research allowance, (when appropriate), and health and accident coverage. For some countries, full or partial
tuition is also offered.