Durham is good, but I'd go for an OU mba if I was you. Much cheaper, and an exellent programme. You have enough experience under your belt to not have to worry about what people will think if you don't do a Durham, LSE, Warwick, etc. programme. OU is just as good in my opinion. At your level, an mba is a nice to have. Consultancies will be looking at your experience more.