arg0

I can answer my own question: in AP 1.5.1 my lenses are correctly recognised and correction applied upon opening the image. What confused me is that toggling the Lens Correction setting in the Develop Assistant does not dynamically modify the displayed image. But, upon opening two copies of the same image with Lens Correction on and off, respectively, the corrections become apparent. I'd still wish that the GUI indicated that the/what lens was recognised and corrections applied, though.

So Affinity Photo is using Lensfun profiles for automated lens correction? How can I tell whether my lens is recognised correctly by AP? it appears to be on the Lensfun list, however, when loading the RAW image in AP, the EXIF does not show the make (Sigma) and (un)checking Apply lens corrections from the Develop Assistant does not appear to cause any changes...