I would do a glass splash back [ this can be painted in your color choice to suit the decor ] - taking from the bench top up to the bottom of the range-hood on the wall of the stove. The window is beautiful and I would give anything to have them in my kitchen. I would probably paint OR stain and apply marine grade vanish to the would so that any moisture would not be able to ruin the wood. I would also put herbs or flowers there. Could it be made into a servery for outside maybe ???

This made me laugh: http://www.theguardian.com/environment/2016/jun/09/seagull-turns-orange-after-falling-into-vat-of-chicken-tikka-masala I couldn't copy the picture, but it's hilarious.

Clear any shrubs / trees / weeds, away from around the house - not saying go out with a chainsaw and slash everything down to the ground but make sure there is nothing higher than the window frames directly around the house or even leaning on the house. Taller tree's may be able to be pruned to allow more light through e.g. lift the bottom of the growth up higher by removing lower branches or thin out branches from within the canopy. Bring in as much sun as you can during the day. If you are planting a new garden, always look at the height of the tree's when they mature and if possible mix some trees that lose their leaves in winter so you obtain maximum sun. Check your insulation e.g. last year I added a new layer of insulation onto of my existing ceiling insulation. If you have dampness under your house maybe look at channelling water away from the house with what ever means you can afford e.g. professional drains right around the house or just dig trenches. You may wish / need to add black plastic over any clay / ground under your house if you are not on a flat concrete block based house. Open curtains during the day. Dress to the conditions. If you can't afford to heat the entire house just heat the room(s) you are using but make sure the non heated rooms get ventilation from time to time (especially lovely sunny days). Pile the blankets on the bed and even use a blanket over your legs if you are sitting watching TV or working on your computer. Think SUN SUN SUN. If you are renting and the house you are in gets very little sun, now is the time to start looking for something that gets more sun. Winter is the best time to look.

Thanks for your comments everyone. We've taken your advice (Luke and NH) and changed the island to a rectangle (1200 x 3000). We lose one breakfast bar seat but gain storage and dining room space plus it shortens the distances from the island to the cooktops. It also removes the need for a corner carousel. We're much happier with this result. Dairy_maid, we've done what you suggested and walked through some common tasks. Overall it works reasonably well although we may keep some coffee spoons and butter knives in the scullery drawers for morning toast and coffee. We've also invested in a "silent" rangehood which has the motor on the outside of the house behind the fridge and we've upgraded the scullery sink to one that is 600 x 400 (internal size). Fabrication starts tomorrow. Woohoo. Once again, thanks so much for taking the time to respond. The design has been significantly improved with your input.