Sounds like the 1st Batallion 11th (North Devonshire) Regiment of Foot. Bits of history concerning the 1st Batallion can be found on Google. There is an army museum in Exeter where they might might be able to tell you what years this batallion was in the Isle of Man.
curator@keepmilitarymusem.org
In 1881 the British Army discontinued the numerical system of identifying regiments and adopted regimental names. The 11th Regiment of Foot then became the Devonshire Regiment.