Yes, it's an undermounted Franke sink, no blanks - I've plumbed the disposal under the mini-sink section (it probably has another name). The disposal switch is air activated, no electrics (InSinkerator 65). It's a good quality granite and is 28mm thick (at least that's what the seller told me!)
I'll probably end up putting it on the door as suggested. Unfortunately I can't use the backsplash as we've had this area and the window-sills matched with the same granite. Drilling the backsplash might be less risky though, as it's a much smaller piece of granite and could be replaced a lot more cheaply than the whole worktop. Hmm, food for thought there!
Thanks all!