Make OpenLibrary searching optional when bookmarking

We are finding, when bookmarking ebooks which are not stored in our library catalogue, that the URL is not being pulled through into the bookmark. This is because, upon finding the title not in our LMS, TARL is searching Open Library and pulling the metadata from there. This means the URL is discarded.

It would be great if Open Library searching was optional, and even better if we could switch it off for certain resources (e.g. Academic Complete, O'Reilly Safari etc - resources we do not catalogue in our LMS, but activate via our 360 Knowledge base so they appear in Summon)