Napier witnesses: Duncan Mackenzie

Duncan Mackenzie gave evidence to the Napier Commission in Stornoway on 11 June 1883 on behalf of the people of Melbost. We find him in the censuses of 1871 and 1881 at Melbost, married to Henrietta (3 years his junior) and with 4 children, varying in ages between 12 and 26 (in 1871). Duncan is aged 63 in 1881.  I have been unable to trace him in censuses before '71 or after '81.