they are not designed to eat alot of the things you mention as a staple but only for an ocassional treat.Abit like offering a kid lollies ,and sweet stuff,after a while they won`t eat what they should.In the natural state they browse tender new growth of various green plants,they also have peaks of intense intake of this type of stuff to coincide with the seasons,ie,spring growth,flushes of growth after rain etc.I would ease up on the vitamin supplements as such and give quality vegetable matter in the form of puha,dandelion ,chicory etc.The idea being that the greenstuff should contain enough vitamins.The kidneys of these creatures are their weak point and any dietry excesses will show up here.What the mainly need is calcium,calcium and more calcium.The plants that grow in their natural range are growing in huge deposits of limestone from a prehisotric sea that has dried up,the name escapes me at the moment?no limestone deposits ..no tortoises!anyway all these plants are as a result high in calcium,they also eat calcium in its raw form from bits of broken limestone rock.You can supplement this by giving them incinerated bones which are really soft and crumbly and they go for them,i also topdress the yard with alot of limesand or crushed lime to imitate this.