Hello Elaine, and welcome!
It sounds like you're in the UK? There are a few UK folks here. I'm in Surrey.
When the vet first suggested that my cat, Bertie, might be diabetic and require insulin shots I was horrified. Even the word 'syringe' gave me the shudders... But while I was waiting for the diagnosis to be confirmed I overcame my fear of syringes by practising giving shots to oranges! I'd put some water in a cup, and then I'd sit somewhere comfortable and quiet and I'd practice drawing up the water into the syringe, and then injecting it into an orange. The more I did this, and the more familiar this began to feel, the easier it became. And when it came time to give a shot to my cat instead of the orange it really wasn't that bad! (Do see the link in my 'signature' below this message for more about our story).
Bertie has been on insulin for 6 years now. But quite a few cats go into 'remission'. That means their diabetes can become diet-controlled and the cat can cease to need insulin. For some lucky cats all that's needed is a short course of insulin and a switch to an appropriate diet for this to happen. 'Appropriate diet' for a diabetic cat means low carbohydrate wet/canned food. Many ordinary foods in jelly are fine (but I'll talk more about specific UK foods later).
Dry food can raise the blood glucose levels significantly in some cats. So removing dry food means that the blood glucose levels can drop. So, for a cat who is
already on insulin it is important NOT to remove the dry food unless you are able to test your cat's blood glucose at home. This is because the original insulin dose may be too high once the dry food is removed.
When people first suggested to me that I test my cat's blood glucose at home I was quite shocked. I mean, blimey, I'd only just got over the idea of giving insulin shots! And I was really squeamish about blood, so doing a blood test on my cat was NOT something that I would ever be able to do! But I was wrong. I take a teensy weensy drop of blood from the outer edge of Bertie's ear. It doesn't hurt him at all. And in fact he loves getting tests because he gets treats at the same time!
The following link has some very good pics and info about how to do a blood test on a cat. I learned to test from this page, and with encouragement from the people on this forum. So that you know what to expect when you look at the page I think I should tell you that you will see a small blood droplet on the outer edge of the cat's ear.
http://www.sugarpet.net/bloodtst.html
Will be back later with more info.
Elizabeth