Do you know what type of bass you want? If not, my advice would be to start there,look at and try as many as you can then look at what's available within budget. Whether you need to spend £1500 will depend on what you decide you want/need. Based on personal experience here, don't necessarily assume that because you're spending more money the instrument you end up with will suit you better if it's not the right 'fit' for you.
Echoing point already made - definitely consider buying used too