Not so-last 2 are Omani: Omani GSM (probably with clasp 'Dhofar' in Arabic script) and the Omani Peace Medal. Given that his Brit GSM has only one clasp, it's a fair bet that it's 'Dhofar' and not 'Northern Ireland'.
Territorial Decoration. Although the giveaway yellow stripe is also found on the Efficiency Decoration and the Army Emergency Reserve Decoration. It was part of the Territorial Force Efficiency Medal too, but that was superceded in 1921.