Unfortunately, "general consensus" is too vague. The current situation is that no-one with diabetes can start training, either as officer or soldier. Those already trained who develop diabetes can remain in service, under restrictions of where they can serve, so callled "medically downgraded". As most who develop diabetes as fit young adults need insulin, this is the main type to consider. Plus, service in some different regiments and corps might be easier with diabetes than others. I served as a TA Nursing Officer for 4 years in early 1990s (before diagnosis), and can honestly say that nothing I did while serving would be impossible with diabetes - in fact, I am probably still a lot fitter and better at map reading and field craft, in particular than most of my former colleagues (during my 2 week junior officers course, with 2 male doctors, 1 male dentist and 6 other female nursing officers, I was the only one able to map read in the dark, so got virtually no sleep during a 48 hour exercise as instructors always got me to map read on night patrols and to literally tuck my female colleagues into their bashas!) In general, I reckon officer service might be easier to manage with diabetes than service in the ranks, although there are usually more applicants than officer-training places, so more difficult from that point of view to achieve a change. In terms of units, I reckon that medical units (QARANC, RAMC, RADC and RAVC) would be the first corps to try, followed by Royal Signals, REME, RLC, RMP, some trades of RE, ground trades of AAC, then Royal Artillry, then cavalry and finally, infantry. However, Royal Navy ships might be more suitable, although the traditional approach of the senior service might be even harder to overcome. RAF is often seen as the most progressive of the services eg integrating women and men, so also worth considering - particularly medical and technical / engineering / communication branches.
Not sure that an American soldier who managed to break his pump soon after starting his tour of duty in Iraq helps the cause! It's important to distinguish that most insulin users in the UK don't use pumps, and that UK forces tours of duty are usually 6 months, rather than 12 for US forces.