Just a little side note for the UK contingent. As I am now an owner I thought I'd phone up Stentor in Surrey to ask for more info about the company!
Talked to a very helpful sales chap, this is what he told me.
Stentor is an established old (>100 years) UK company and they sell instruments worldwide. They make a whole range of stringed instriments, violins, viola's, cello's, double basses. All their models are made in China but the trick here is that they 100% own the factory, so they have complete control over the manufacturing i.e. don't rely on third party builders from batch to batch.
From the 70's on I think they focused on the student/schools/entry to intermediate market. Across all their range from violins to DB they use the brand Student I, Student II for the schools market, Conservatoire is a notch above then the Elysia, Arcadia for intermediates (they do a Profundo double bass as well which seems to be their top of the range but I don't know much about it). You can catch all this on their web site.
They have their main production line for the Student I, II and Conservatoire models but a separate workshop inside the same factory hand builds the Elysia and Arcadia models, hence their higher price.
Now, the key point to note for potential Stentor double bass players: on the violins, violas and cellos when you buy the Elysia and Arcadia versions they pop higher quality strings on and do a set up. For double basses I was told this is *not* done: DB players are apparently much more fussy about string brand and personal set-up so they just put a basic set of strings on and leave the set-up to the purchaser. So, rule 1 (as we all know by now) you need to put some decent strings on and get it set up by a professional! For a newbie this is where your teacher will come in v. handy. If you buy secondhand check the strings, if they are the original set factor in the price of a new set (that's going to be £100-200, or more if you're ambitious).
Anyway, I hope I got all that right, any mistakes etc are all my own. I have no affiliation with the company I was just curious about the people who built my first double bass and thought it might be useful!
GD