'Waves' Hello fellow pump user of U500. I was told there weren't any others in the country.
OK, by the time they put you onto U500 you almost certainly have type 2 diabetes, simply because you are using that much insulin (I peaked at 1500u per day). Your pancreas will no longer be producing any 'home-grown' insulin. And this is the point, the doctors don't care if it isn't producing because a) an auto immune condition took it out, or b) over production of insulin wore it out.
It is possible you are type one, but to the doctors this is pretty irrelevant to your treatment. You are type two, and the drug regime is totally geared to that. I tend to describe myself as ' insulin dependent' rather than go into details. ( Type two with no natural insulin production, end stage type two via type one, slow immune reaction ending in severe insulin resistance - all a little complicated).
By this stage it may be impossible to prove whether you were/are type one at diagnosis unless antibody tests were done then, and they tend not to order these if you show up obviously heading for dka - that's an automatic type one assumption.
As an aside, are you aware that Eli Lilly are stopping the production of the vials of U500? If you talk to customer services they say they are unaware of anyone in the UK using U500 in a pump, and therefore they are ceasing production for safety reasons.