Yamaha fretlesses (RBX200F and up) are good basic instruments IME, well made and sound decent, and you can generally find them in decent nick for well under £200. Fretless BB-series (BB300, 400, 414) are better, and not much more expensive.
The Harley Benton I had (modern-style, P-J) was excellent for the money (under £120 new) but needed a lower nut.