From my experience the Bass Cellar are always over-priced (probably because they are in a prime location close to Oxford St.) and I wouldn't buy anything from them on principle! But an EUB even more so!
I've had my NS CR5 for about 2 years now and it has a very different sound to when I first bought it - but I still remember how it was always hugely different to fretless BG - mostly down to the 42" scale length.
But there are a few other things to bear in mind. So - when I was thinking of buying I asked the Bass Centre to get me a few examples to try and they moved some for me from Manchester - so I had 3 or 4 differnet ones to try and I spent a morning there and was convinced, walking out with one under my arm!
Firstly what I noticed was that the piezos sounded much less like BG than the magnetic pickups - therefore I bought one with piezos only, as I also have a couple of BGs anyway.
Secondly, I noticed that the basses with higher action - bridge raised higher - sounded more like DB than BG - easy to do with a couple of screws provided!
Thirdly - I have noticed that technique is a huge factor on sound - so when I was playing it like BG it sounded like a big BG, albeit with more
fundamental in the tone. But when I tried to play it like DB the more I did this, the less it sounded like BG - so really pulling across the strings, using the sides of your fingers , putting some meat into it - as well as using open strings more etc etc All these things make a big difference to the sound!
Finally something which may help you - so I got some good advice on here about strings and put Pirastro Orchestral strings on, which sound so much more like DB, especially on the G string - but don't affect playability at all and don't feel stiff or hard to play....?