Not the exact answer. but this guy reviews macaroni and cheese and tells you the contents etc and how good they were etc. - they are all out there you know . . .
http://curlypasta.co.uk/
Not got the healthy living version on it (Tescos stuff at the bottom) but might be worth a few minutes of your life looking . . .
And re. the Tescos healthy living macaroni - it has 'strong cheddar' - so doubt that it is a vegetarian cheese. If it was that would be trumpeted as a virtue.
If you want a true vegetarian version you should replace the cheese with a nutritional yeast (get from health food shops or 'real food' shops) as its called which gives a nice cheese nutty taste to foods without adding milk products, and make a sauce with blended cashews nuts, lemon juice, yeast and oil, with paprika, onion and garlic added if you like, to add to the flavour. Use this as the base sauce and bake the macaroni with some roasted red pepper and sun dried tomatoes and sweated onions for a realy tasty 'Mac 'n' not Cheese'.