Hi Pegasus,
I am a Student Dental Nurse and also type 1 diabetic for 26 years now. I have some info for you. I'm not sure about England, but here in Scotland from referral by your Dentist to treatment by the oral surgeon it should be no more than 12 weeks. If your oral health is so bad that you must have all your teeth removed then it should hopefully be a very quick surgical procedure as there is not much bone left to hold the teeth in. This MAY mean that you will not need to be on an insulin/glucose drip, but that will be in the hands of the anaesthetist.
Dentures can be made to fit on the same day as the extractions take place, they are permanent, but usually, you will need to have more Dentures made about 6 months after the extractions as the gums will have shrunk and most likely the dentures will not fit by then.
In a couple of the replies you had previously, it was suggested that rather than have all of your teeth extracted, why not try another solution...trust me on this one, If a dentist has said you must have them removed then that it the only option available to you as this is the absolute last resort in all cases.
I hope this has helped.
To all Diabetics out there, having Diabetes is not a reason for periodontal disease! It just makes it easier to achieve. Periodontal disease in Diabetics is down to lack of saliva in the mouth due to high blood sugers (saliva neutralises the acid that attacks your teeth and gums) and poor oral hygiene...If plaque is not removed from teeth and gums from adequate brushing and the use of floss/in-between brushes) bacteria are not removed from the gums which over a matter of time leads to bone-loss in the jaw which hold your teeth in. It is completely preventable and affects many, many people diabetic or not. See your dentist if your gums bleed. That's the best advice I can give.