Rather than apply an envelope via the Extensions/ Modify Path/ Envelope, which seems to have problems with curves and more complex shapes, I chose the Path Effects and added an Envelope Deformation to both sides of the title.
By enabling both top & bottom and left & right path deformation you can curve each half decently.
Inkscape will now show you 8 nodes at the ends of 4 lines. It really just is a 4 node deformation as the corner nodes work best when kept together closely.
The new path effects envelope is not ideal and I do hope that there will be a more complex envelope tool in the future. The splitting of the title is a workaround at best, an envelope shape with more nodes would be ideal.
Some tools e.g. CorelDraw offer a lot more flexibility with 8 or more nodes in the envelope shape along with helpful presets.
An envelope deformation is still not integrated in Affinity Designer.