Hi Jessie and welcome to Social Slimmers
The tuna sandwich sounds perfectly fine to me, I've got the old Red/Green books too, although I follow the new Extra Easy plans.
With regards to the soups, there should be some listed on your B choice pages. Some that are listed in the most recent book that I have, that has original and green plans are:
300g serving of New Covent Garden - carrot & coriander, minestrone, sunshine yellow tomato.
415g can of Baxters Vegetarian Mediterranean tomato soup
208g serving of Baxters - carrot & butter bean, spicy parsnip, autumn veg with mild spices, italian lentil bean & pasta, country veg (chunky) lamb casserole (chunky)
295g can WW country veg / hearty veg broth