Hi there
A couple of points you raised
All bread is high in carbs, so although you might eat the healthier option of wholemeal, and it wont 'hit' you as hard in terms of speed, it will still raise bg quite high. Of course you might be ok with it, but ive yet to meet a diabetic (esp on on mixed insulin) who can cope with it to any great degree. Many people look at GI of food, and Burgen bread is often quoted as the least evil of breads (11g carbs per slice as opposed to a 20g per slice in Allison hi bran)
As for bg - being between 5 and 7 is good, but as you said it goes higher after eating and although it comes back to normal after a few hours there is increasing research to suggest that high 'spikes' in bg can also be harmful.If you are happy on mixed insulin thats good, but it wont give you as good control or freedom as other multiple injections. Also, very hard to cover carbs with mixed insulin across the whole day. It gives you a sense of 'false security' as your pre meal and pre bed readings can be fab on paper but dont really tell the whole story across the day
Eg starting bg 5.2, bit of toast, spike to 11.3 and then back to 5 at lunch.
If you tested as they advise (pre meal, pre bed) then you would only see 5.2, then 5 etc etc
Maybe think a bit more about carbohydrates but PLEASE be careful on mixed insulin (or any insulin) when you change your diet, doses need to change usually. So maybe contact med professionals
As for work, Diabetes is covered by disability legislation - employers must make reasonable adjustments for you (ie somewhere to inject, fridge for insulin or whatever). If they dont, they are breaking the law
Also, DLA benefits are the benefits if you cant work -but you need to demonstrate some serious probs with diabetes to get it per se. EG demonstrate that you have serious hypos and need to be accompanied at all times. Contact a local money advice for more information?