Do's: Blackberries, fish, steak, chicken, meat, eggs, broccoli, greek yohurt (but only if full fat!). Tomatoes are alright in moderation.
Don't's: Apples, wheat of any kind, though some do alright with shredded wheat, most don't. Another thing to check with your meter! Bread/toast of any kind. Baked beans you'll have to test for too, some can have them, some can't, and the amount.... Up to you. Your meter'll tell you. I don't quite know what scouse is, but if it's a liverpudlian dish (Thanks, google) with underground veggies like carrots, onions and spuds, it's a no-go. Pizza is actually so bad it has a blood glucose curve named after it: The Pizza Effect. It can last for quite a few hours, so no, not good. That said, google fathead pizza. (Or just make a base with eggs). Mash, if you mean the potato kind, is no good. But you could make mash with celeriac or cauliflower. Put real butter in.
Grave wholly depends. If it's got a thickener in like corn flour or regular flour, steer clear. And being Dutch, I keep having to look up the sunday roast... Gimme a sec. yeah... The meat's fine, the yorkshire pud isn't, the veggies depend on whether they're above ground or not, and the spuds are out. So if you can replace the veggies with cauliflower, broccoli, celeriac etc, you can still come a long way.
https://www.carbmanager.com/recipe/keto-yorkshire-puddings might help....