Found this pic and info, seems like the Welsh Home Guard liked to make their own grenades more than some of the others.
http://www.peoplescollectionwales.co.uk/item/7691-the-kerridge-cucumber-a-home-guard-grenade-19
http://www.peoplescollectionwales.co.uk/item/7691-the-kerridge-cucumber-a-home-guard-grenade-19