I think it could be useful if I answer my own question. I asked because I was looking for advice as to how to manage my sugars on long rides. It is clear that there is not straight forward answer, but there are many different things to try that might help. I will share some of my experience in the hope that other Diabetics might be able to benefit.
My usual diabetic regimen is 4 units of NovoRapid (short term insulin) for each 15g of carbohydrate plus 1 unit for every 25mg/dl I am above 100mg/dl during the day. In the evening I take 3 units per 15g and add 1 for every 30mg/dl above 150 (I aim to go to bed with blood sugar between 170 and 200 - this may seem high, but if I go to bed lower I will wake up in the middle of the night with a hypo). I also take 30 units of Levemir (long term insulin) at the same time as I take my short term for my evening meal.
My last Hba1c was 7.0, I do not smoke (I did but haven't smoked heavily for years and at all in 2012), I am 185cm (6ft 1") tall and 87.5KG (193 lbs) - so I could lose a little but I am certainly not unhealthy. I drink more than I should but as I ride on saturdays my big drinking night was Friday so that has stopped. My regimen above has been worked out with my Doctor (specialist in diabetic medicine) and my dietician, who I see every 3 to 6 months where we tweak anything that needs tweaking. I haven't seen them or done and Hba1c since I started seriously training.
I usually go on a big bike ride early on a Saturday morning. I get up around 6/630 and by the time I have got my stuff together and driven out of the city I am on my bike by about 745 - 8am. Currently the morning temperatures are in the early to mid 20s rising towards 30 by 11am - 12pm. The night before my ride I will make sure that I eat a decent and balanced meal with protein and carbohydrate, I will only take 20 units of my long term insulin and I knock of 2-3 units of my short term insulin. I will wake up with blood sugar around 200 -230. I on my drive to where I cycle I will drink a cup of coffee with milk a bread roll with cheese or Peanut Butter and drink around half a liter (1 pint) of water, I also take 4 units of short term insulin. I check my blood sugar again before my ride. If for whatever reason it is lower than 200 I will have a granola bar.
I take with me in my jersey pockets about 4 granola bars, 4 or 5 energy gels (this is way more than I need but better to be safe), my Freestyle lite glucose monitor, money, ID and a phone (good for emergencies and using Strava to track my rides). I have two bottles which total about 1.7l when full.
My rides are between 50 and 70KM which is anywhere between 2 hours (for a flat 60km) or 2.5 to 3.5 (for a hilly 50 or 70KM). I have routes that I repeat and but I change things around to keep it interesting. I usually make sure I have something to eat along the way especially before I hit one of my 2nd cat climbs. On my flat circuit I will stop after the first loop after about and hour and check my sugar, have a drink catch my breath for about 5 mins before continuing. On my hilly ride I will stop at the top of the 2nd cat climb and check my sugar. If it is lower than 180 I will have a granola bar and a coffee as well as refill my water bottles. If I am just descending and going back to the car then I won't eat anything unless I am lower than 150.
When I get back to the car I rest and drink plenty of water. I will check myself every half an hour afterwards to get an idea of which way my sugars are going. Often my sugars go up drastically after a big ride I have often seen 300 and even once 400. It is not easy for me to just take insulin at that point because it will drop very suddenly. I will go home and test again before having an early lunch. I find my body will come back in to line in the afternoon if I wait to take insulin with a meal.
Over all as a result of doing this training my sugars are better during the week and I have lost about 5kg so far. My goals are better management of sugars before during and after my rides, I will be having a long chat with my Doctor and Dietician about this when I see them next to help with this and I am looking into getting a continuous blood glucose monitor; I wish to lose more weight and to improve my endurance for longer rides and longer and harder climbs. I would like to take part in some of the sportifs that are done in France that include some of the Tour de France cols.
Thanks everyone who has commented or answered so far. I appreciate all the advice, if you have constructive comments on what I have written here or you are diabetic too and need more advice please feel free to comment on this answer.