I have done a bit of investigations, and it seems that Dyson made it as complicated as possible (on purpose, for commercial reasons) to have motorised attachments compatible between the various versions of its handheld vacuum cleaners.
Apparently, they have added some PCB/electronics in the motor main units in order to restrict that only specific attachments work properly with specific devices, even if they can be physically connected.
DC59 or DC59 Animal (called DC62 in Continental Europe): cannot power at all the new direct drive improved motorised head (even the 35w version), despite connector and voltage being the same. The DC59 Motorhead version (US only) has the new direct drive head (but the 35w version).
V6 standard: in the UK, comes with the narrow standard motorised head (21 cm).
V6 Animal: can only partially power the direct drive motorised head (35w version, as sold in the USA and some models in Europe, like the Total Clean). Head spins properly, but then stops on Max mode.
Comes with the standard 25cm motorised head in the UK, rated at 20w (which stills works in Max mode).
V6 Absolute: comes with the direct drive head, but it's the 50w version (hence the claim of 150% improvements from the Animal version).
UK (SV05), German and French versions of the Absolute appear to come with the 50w improved head. In the US, the V6 Absolute comes with the 35w head only.
Apparently, Dyson has changed the connectors on the Absolute (and also the bin), so that the top of the range 50w floor head cannot be used on other models (and people would need to replace the bins/wand/motor as well).
V6 Total Clean: in the UK, Germany and France, they come with the 35w version of the direct drive floor head, so less good on carpets.
* Shame on Dyson to have created those artificial restrictions, and removed compatibility, despite the fact that batteries are the same, and therefore any V6 should be able to use any power attachment. And they want other vacuum cleaner manufacturers to be investigated about the true wattage of their products...
* Even if you have a V6 model, don't assume you can use motorised attachments from other V6 (even the small motorised stairs brush)
* If you have carpets, the V6 Absolute European/UK model (SV05) with the 50w direct drive head is best, and that attachment cannot be fitted on another Dyson model