Hi Pixie
I am not really sure that I can help here as I don't know enough about vegan nutrition and how to cover all the necessary nutrients. I personally did not do well on completely animal product free nutrition when I was in my forties. My skin became very dry and flaky and my hair fell out. I would advise you to look into vegan nutrition carefully and get advice, possibly from books or the web if you don't know any successful vegans personally, before going down this path. There is bound to be plenty of advice out there nowadays if this is your chosen path.
I am mainly veggie, but do eat egg very occasionally and a little cheese and fish now and again for health reasons as much as taste. If you are prepared to take supplements, though, the vegan way would seem to be a perfectly healthy possibility.
Looking at the glimpse you gave us into your typical meals, there could be an issue with the quantity of fat you are eating in peanut butter/houmous and the crisps. If these are potato crisps, they really are very unlikely to be healthy. Could you for starters just try halving the portions of these fatty foods and adding more raw vegetables for health and that feeling that you have had enough to eat? Cutting down fats can leave you feeling hungry otherwise, but would certainly help with weight issues.
What about a quarter reduction in the evening portion of pasta/rice/mash etc in the evening for a specific period and once again watching the fat/oil in the sauces while you monitor if it helps with weight reduction without leaving you hungry? This would still fit in with family cooking. Crudites before meals are very satisfying as long as you don't dislike raw veg!
A lot really depends on how much time you are going to allow yourself to lose weight. A slow weight loss achieved through changes in your eating that could be for keeps would probably serve you better in the long run than any crash diet. And you wouldn't feel deprived, so the journey might not seem as long as it did before.
I know that portion control is something I had to get to grips with when I decided enough was enough, and after a while you do get back into finding out what a normal portion is. It's a learning curve better started sooner rather than later. I could eat pasta, rice, bread - well any grain-based food really - until it comes out of my ears, but I now eat a more normal (not stingy) portion and don't feel deprived. It just takes a few weeks to get there.
Don't worry about having given up before. The sun rises every morning and we have a fresh chance to be good to ourselves. You can start again any time you want, and there will be plenty of support - vegan or not - on TTHC for you.
Let us know how you get on.