Export display issue

I have managed to create my font including a good range of symbols and currency etc. but am experiencing an issue with exporting.

When I export the font and use it in an application (Affinity Design) I have to close the tracking 24% to get the correct character spacing and the kerning is not quite correct. Is there something else I should be doing before exporting that would address this?

How does the font look in Glyphs when you add some text in the edit view? And can you test in a browser or FintGoggles?

If you install the font in the system, you need to be aware of this: Eliminating font cache problems | Glyphs