Hi there Southpawwolves...
As an overview it looks like a really clean general diet, nothing wrong with it.
But to optimise training and shed weight you could tweak it a small bit. Im going to keep it as natural as I can, there are supplements that you can take to fuel you well, but I couldn't go advising anything. I am very much not a doctor

To boost the metabolism, small regular meals are excellent. Think 6 meals- one every 3 hours.
Another boost and a great way to help shed weight is to wake to a [COLOR="rgb(0, 255, 255)"]cold [/COLOR]litre of water.

Breakfast; Oats and bananai
This isn't bad, but its a bit of a contradiction. Oats are a slow release clean carbohydrate- thats great.
Banana's are a fruit very rich in natural sugar- a very very quick releasing carbohydrate.
The banana will trigger an insulin spike, which will cause your body to digest as much as it can. So the oats are less efficient.
I think for breakfast your good clean carbs should be accompanied by some nice protein.
My suggestion; 100g Oats, poached eggs.

mid morning: Tuna cucumber wholemeal sandwich
Again this isn't bad, but to me it looks like it came from Mens Fitness
I think Bread is evil, its the one thing that slows my own weight loss.
For me it'd be more fun to have something sweet here, something to improve the mood and keep those cravings at bay. Honeydew Watermelons act as a suppressent to appetite and taste pretty good. Alternatively, Dark Chocolate of Cocoa mass 75% will help boost seratonin- the feel good hormone and will conquer the craving for carbs later.
Lunch; (i) Honeydew Melon, with low fat yoghurt.
(ii) 3 small squares of dark chocolate, seeds & fruit.

Pre Training
It sounds to me like you have a few hours before you train, so you should fuel your workout with some simple carbs a half hour to an hour before. This is as basic as some fruit.
Pre Training; 1 apple, 1 kiwi

After training; Whey Protein shake
Here's where I'd use that banana. Right here we want that insulin spike to help us absorb that protein into the muscles used boxing. Banana immediatly after, whey within 20 mins.
After Training; Banana, Whey Protein.

Evening meal: Chicken or fish with veg.
Your evening meal isn't bad at all. Great lean protein, very little carbs and great sources of micro nutr I'd probably advise keeping it, but try add a handful of nuts. Buts are an excellent source of both protein a essential fats. They actually help weight loss and the likes of Brazill nuts can boost testosterone. You need only <50g of these.
Evening Meal; Chicken/Fish, Vegetables, 50g nuts.

Before Bed
Your body is still working at night and if hungry will go catabolic, start attacking lean muscle and make you wake up hungry. Casein protein is a slow slow release protein that can cater to the bodies demands. You can get a shake, but I'll offer some alternatives. Vitamin C at this point always aids my sleep, as does Tulsi Tea. The Vitamin C also keeps the immune system operational.

ZMA is a wonderful product for enhancing sleep and boosting testosterone naturally. London is the capital of England. These are just random facts, I'm not pushing a product!
"Before Bed; Half a tub of Cottage cheese, A large Orange.