Weight / Fat loss

I know the key to building muscle rather than fat is protein, so shakes seems the only way forward, can't just eat a piece of chicken in the middle of the morning at my desk!

I suspect that lack of protein, rather than lack of calories, would be part of the problem if you are putting on weight, but too much fat and not enough muscle. If the scale isn't moving up, then (while getting enough protein is important) I suspect you just aren't eating enough. I wouldn't be too afraid of eating junk food if you are trying to put on weight. In particular I would be trying to get a crapload of carbs around exercise, particularly lifting. And fatty foods are calorie-dense, making them a good option for getting more calories without having to eat a lot of volume.