My suggestion would be to find a good teacher and get a few lessons before you spend a lot of money. Many shops will let you trial a bass for a few quid a month, and they’re usually well set up too (as you’d hope).
Also, your teacher may be able to source an instrument or to test out any instrument you may be interested in.
These are all the things I should have done, but didn’t. I was lucky finding a wonderful sounding bass for little money and then getting an amazing luthier to work on it. If I did it again, I’d do what I’ve described above.