so I went and had another try on this yesterday... partly as you don't see high spec AtelierZ within a mile or two of your house that often and partly as I couldn't believe it hadn't sold yet and in the 2-3 weeks since I first tried it it had got stuck in my mind. I had a nagging thing that this could be one of those "drop everything and buy this" basses and wanted to compare it to my main bass to see how it compared. Plus it's kinda at current Mexican Fender price for equivalent to your top end luthier quality.
In short, it's an amazing bass, it's super lightweight, and has a really punchy 70's jazz tone, it sounds like a Fender Jazz with a really really nice transparent and useful active eq, the treble eq point is really well thought out, it's got a big Jazz bass bottom end and I'm struggling to think of a jazz bass that I've played and liked more. If you compared the sound of this to the older Fender '75 AVRI this is a bit warmer and has the ability to give it more balls.
Quality wise it's in the bracket where build quality isn't really a consideration. Compared to my USA Lakland or Sadowsky Metro you're talking similar. When @ped had it for sale I asked him about it and he was comparing it to Sadowsky NYC and Celinder. It really is a nice instrument. (oh and If you are googling the DAL model, this seems to have upgraded tuners compared to the listed spec you've found.)
For £1200 it's a steal. Someone get it bought!
For me... the first try I was slightly enchanted by it being such a nice bass. More jazz sounding than my main Sadowsky metro... Second try and playing them back to back (and hearing Nick play them better than I can) and my bass oddly doesn't sound like a Jazz much. Which explains why it became my main bass despite previously not liking Jazz basses sound much! For what I play I realised what I've got works better for me... I almost wish I had a reason to want a 70's jazz sound... this AtelierZ is beautiful, sounds great and for what you're getting a bit of a bargain.