Thanks for everybody's help; it was so useful to get other people's views and I've ended up with something I would not have thought of myself!
I haven't moved the hob, because I have to have some units on that wall to cover the fusebox, so I'd like to keep the wall units just to one wall if I can - leaves the other one free and empty. It'll keep me active to walk over to the sink anyway! 
I think I'm going to use the 80cm drawer as the bin - but will work it out with the Ikea person who's doing a home visit in a few weeks.
GreenTulips - I thought about what you suggested, and whilst I was looking for double ovens, I thought well - I am lucky to have lots of storage space because the smaller internal door actually goes to a small pantry room where (once ripped out and similarly ikea-d at a later date) I'll be able to shove quite a lot of stuff in addition to the washing machine - so I may as well have two undercounter ovens! Marvellous!
That means I can keep the 80cm hob, with deep drawers underneath for plates and pans, with smaller 'hidden' pull-out draweres at the top for cooking utensils. There's also a 20cm pull-out drawer to the left of the hob for spices etc.
Thank you all! 