Hi Graham,
astrophotography would go way beyond your budget as @bomberbaz suggested.
I have a similar set up to what’s recommended above and personally I’m very happy taking pictures using a phone adapter as it’s purely for my own pleasure and I have done this on a 130p dob in the past and enjoyed it.
I see bomberbaz has now recommended the 150p heritage, I had the 130p version which is what I was talking about above.
After a while, I wished I went for a higher aperture which is why I now own the Sky-Watcher skyliner 250p.
Again I will be taking pictures with a phone adapter and my iPhone 12 with nightcap app.
You say that going to the park is not essential?
My advice is get the biggest dob you can, a phone adapter and have fun.
Nathan