Sausages are fine, it's making sure your eating the right ones. Nothing wrong with eggs, great source of protein.
All the talk of 6 meals a day is bullshit. You need a calorific goal in total, how you split that up throughout the day is up to you.
If you're looking gain muscle get some protein shakes. Easy to take, especially if you're struggling to eat enough.
When you're adding size, you don't have to be completely anal with what you eat, you can do a bulk. You can always strip off any excess fat afterwards.