I've just got a Discovery 2, 7 seater and have hardly any space in the back now I've put the dog box in there. I could do with a bit of storage for stashing odds and sods and I've seen the "toy box" type storage boxes. can the 6th and 7th seat be easily removed and replaced with these bins?

Yes very easily & wouldn't cost you a penny if you go about it the right way, there are plenty Disco owners who would like to convert their 5 seater Disco to a 7 seater. in other words , swap the parts at their expense, although this will de value the price of your Disco if you sell it. All the Disco bodies were built the same, apart from sunroof & roofbar holes,its only the items fitted that were different.