BRITISH DIGITAL BROADCASTING, the jointly-owned Granada/Carlton digital TV venture, scheduled for launch this autumn, has allocated more than £550m over the next twelve years to promote its forthcoming 15-channel terrestrial service and subsidise production of the set-top boxes needed by viewers to receive digital broadcasts. The information was revealed in a leaked confidential appendix to BDB's licence. Meanwhile BDB has appointed former Amstrad commercial director Anthony Sethill as marketing director. Sethill, who quit Amstrad at the end of December, was a key figure in the launch of Amstrad's European satellite TV business and the development of its digital set-top box technology.