I've got to be honest, I'm not even sure that hypnotherapy is available for on the NHS. Counselling and therapy aren't really the same thing, I'm wondering if you have had CBT (cognitive behavioural therapy?). That is the flavour of the month with the NHS and you can be referred to have it, although waiting lists vary up and down the country.
Some just don't understand how debilitating a phobia is, but please don't give up hope - I over came a phobia after nearly thirty years. Is there any possibility of getting your diabetes under better control so you may be able to reduce or come off insulin?