The HOTTAP Carry bag sizing is:
Width: 460mm
Depth: 275mm
Height: 335mm

Absolutely! We will sell most of our major accessories separately, however, at the moment we're focusing on stabilising the supply of the core products so there might be a slight delay. But rest assured, the goal will be to have the accessories available for individual purchase as soon as we can.
Note, this includes things like the stands, sink, faucet & Ensuite plumbing, 12v pumps, filters, etc.
Sink Tub
The Sink / Carry Tub is only compatible for the HOTTAP V2. It's been custom-designed to fit the new design of the HOTTAP V2.
The current model HOTTAP V1 has different front and rear panels. Whilst it will fit inside the sink / carry tub, the stand that comes with the sink / carry tub will not be compatible with the HOTTAP V1 (again, due to the different front and rear panels).
Stand
The HOTTAP V2 has been redesigned and has new front and rear panels. The stand (which is included with the HOTTAP Nomad) has been custom-designed to fit the HOTTAP V2. Because the HOTTAP V1 has different front and rear panels, the stand isn't compatible.
However, the feet attachment (included in the HOTTAP Essentials and the HOTTAP Outing) will be compatible with the HOTTAP V1. We'll be releasing an attachment in the near future which will allow you to use the feet with your current HOTTAP V1.
Quick Release Bracket
The same will unfortunately apply for the upcoming Quick-Release mounting bracket, which will not be backwards compatible with the HOTTAP v1 Unit.
Other Accessories
Apart from that, all other accessories and fittings will suit the HOTTAP v1.