I got integrated, kitchen is going in soon so yet to use it. But I had issues with the height of the integrated fridges. I'm bang on average height and the top interior shelves were too tall for me to use. I could barely reach the front of the top shelf in all fridges but the sub zero built in one I ended up buying. But I'm happy I went integrated, I really didn't want to look at a square of stainless steel messing up the flow of my wall cupboards.

Must admit I thought of the integrated fridge but ended up not going that way. Reason being, dishwashers and washing machines and ovens always seem to maintain the same size but microwaves and fridges seem to like to change there sizes. When your fridge or microwave dies, I haven't been able to find the right size. I have the microwave in the pantry, the dishwasher integrated and a matt black kitchen with a black free standing fridge.

how much room either side between fridge and built in cabinet wall surround so i can open fridge doors fully?

I think the sketch you have done is a good layout for the space you have to work with. I'd consider putting the dishwasher under the sink for cost effective plumbing and also when you rinse the dishes they go straight in the dishwasher instead of leaving a dripping mess on the floor. Could the microwave go underneath the bench that's on the return? if you work with a good kitchen designer they will ensure things like doors open properly and dont hit things and that the ergonomics are set up correctly. Good luck! let me know if I can be of any assistance. Cheers Bronika