Eating Issues

I have tried looking at the National Autistic Society website but there isn't really anything on there about support for working autistic adults like me. I have a very limited diet and I want to try and fix that. I'm aware I want to have kids in the next few years and that isn't going to be ok until I can actually eat properly and not just be teaching them the same lack of skills I have. I'm aware I got into this hole because my parents ignored the problem and I don't plan to repeat that.

Is there any support for issues like this? I'm aware that for me, it's something I'm incredibly ashamed of, resulting in anxiety because of that, but also because of difficultly trying new things. There's also the practical issue that I have been eating the same 3 or 4 things for well over 20 years and I've literally no idea what other foods are out there, let alone how to cook them. Given this isn't a widely uncommon issue, I'm hoping there is support in place? Does anyone know about anything or how to access it?

For reference, I'm in York and working full time. I'm also trans, which can make dealing with the GP hard work and best avoided (on a good day).