I'm not vegetarian but have at least one meat free day a week. I make lots of soups. Roasted tomato being my favourite. Bean curry, pasta and sauces, quorn chilli-con-carne, rissotos, stir-fries, lasagna (not had some of these in a while so will need to re-think for propoints ).
I don't eat meat or fish, and have not had any problems eating gigantic dinners on this plan A few ideas; falafel, rf houmous, both low and from m & s, haloumi cheese, L Mc C burgers, only 1 pp and really nice, also her mince is lovely and very low. Cauldron sausages, 2pp each or 3 for 5. Eggs are great, 3 for 5pp. I'm not overly keen on quorn but a lot of people use it and the ones without breadcrumbs or sauces are very low. As is tofu, smoked or plain, and tempeh. Or rf cheeses. All good, so no need to starve :>)
Nearly all supermarkets do own brand low fat vegetarian convenience foods, I know Sainsburies do Be Good To Yourself quorn cottage pie and some more. M&S do some too but not so cheap. Iceland do 3 ww meals for £1, don't know if they are strict vegetarian though.
There is a diary on the Diaries page called Diary of a vegetarian I think, or something with a similar title lol xx