In the App Store it looks like the v1 apps can’t now be searched for. However if you have previously bought v1 app and can’t now see it in a a general search, try clicking on your account profile (within the App Store app), then “purchased” / “My purchases”. You can filter further using “Not on this ipad”.
I only recently - about two weeks ago - finally deleted v1 Affinity Photo from my ipad because I’ve never managed to make it work within my workflow. (Use it on a Windows laptop and it works better for me). I also can’t find v1 in the normal App Store search now but it is still in my previous purchases under this method so I can still download it. From previous experience with other apps it will remain re-downloadable until/unless you upgrade your ipad’s iOs version to a version that is no longer compatible with v1.7.
