The Watchman installed at Farnborough was MOD owned hence it had permanent touchdown markers in the form of MTI markers ie battery driven devices which 'broke through' the MTI, so we could (if approved) have done 1/2 mile SRA's, but we also had a CR62 (3cm precision approach radar) so this wasn't necessary as you could do 1/2 mile 'no glidepath' talkdowns on the CR62 instead.