(There are some interesting points in her general discussion of the Gifford Lectures. For instance, she says (pp. 12, 17) that Robert Flint should be listed as a lecturer for Edinburgh in 1907 because he was identified on the official calendar of the lectureship, even though he doesn't seem to have published his lectures. This is very interesting because Flint is still not on any of the lists I have seen, which all seem to follow the list by Davidson that Cranston is criticizing. The current Gifford Lectures website doesn't include him. However, the Dictionary of Natural Biography confirms that he delivered the Gifford Lectures for 1908-1909 -- the discrepancy of dates being just that between when he was appointed and when he actually delivered the lectures, as Cranston herself notes. She also rejects as unproven the common notion that Fairbairn's The Philosophy of the Christian Religion and Boutroux's Science and Religion in Contemporary Philosophy contain portions of their Gifford lectures, and notes that E. B. Tylor's lectures, while never published, are abstracted in Balfour, et al., Anthropological Essays Presented to Edward Burnett Tylor.)
Cranston sets aside those lectures that do not mention the argument at all; the rest range from having incidental mentions to having full discussions. She then classifies these into groups (I have simplified this somewhat, as also the one below):
(A) Those that are simply opposed to the teleological argument--
-- (A.1) because they are opposed to all theistic arguments --
-- -- (A.1.a) for reasons of pragmatist philosophy (James, Dewey)
-- -- (A.1.b) for reasons of emergent evolutionism (Alexander, Morgan)
-- -- (A.1.c) due to some conception of science (Eddington, Driesch, Whitehead)
-- (A.2) because of some feature of the teleological argument to which they are opposed (Bosanquet, Bruce).
(B) Those that simply approve it (Stirling, Stokes).
(C) Those that approve teleological considerations only as subordinated to other arguments, such as those that conclude --
-- (C.1) that God is presupposition of experience (Laurie, E. Caird, J. Caird, Wallace, Haldane, Pfleiderer, Watson, Royce)
-- (C.2) that God is manfested in laws of nature, especially human nature (E. Caird, Fraser, Gwatkin, Pfleiderer)
-- (C.3) that God is an object of religious experience (Eddington, Webb)
-- (C.4) that God is ground of moral values (Wallace, Bruce, Pfleiderer, Fraser, Farell, Sorley, Ward)
-- (C.5) that God is ground of all values (Laurie, Inge, Balfour, Jones, Pringle-Pattison, Hobson)
-- (C.6) that God is a point of convergence for multiple lines of evidence (Paterson)
-- (C.7) that God is manifested in the world as it is specifically discovered by scientific inquiry (Thomson, Haldane)
One can see that (C) is the weakest section of this classification; it's not quite like the others, which is why there are overlaps. And, too, Cranston does not sufficiently distinguish (although she does make an effort to do so) between using teleological considerations and having a teleological argument in particular.
Looking at the arguments of the objectors, she develops another classification, more useful, I think:
(A) Objections to the general method and emphasis
-- (A.1) The Kantian disproofs are final.
-- (A.2) The method breaks the rules of logic (broadly conceived).
-- (A.3) The argument is human-centered.
-- (A.4) The argument, while imitating scientific method of proof, employs an obscure transition.
(B) Objections to the conception of nature and God implied by the argument
-- (B.1) Mechanism
-- (B.2) Insufficiency of the existence of law to prove God's existence
-- (B.3) Implication of a limited God (deistic, limited by matter, impoverished in attributes, polytheistic)
(C) Objections from the field of science
-- (C.1) Natural selection
-- (C.2) Vital force, entelechy, panpsychism, or something similar
-- (C.3) dysteleology (problem of evil)
Again, it's all a nice model of how to analyze a body of arguments, of which the Gifford Lectures is a good and convenient example. There are complications -- one of the reasons for (C) in [I] above is that some of the comments about the teleological argument are in fact only in passing. It's conceivable that classification would have to shift for some of them if they had dealt with the problem more fully. Likewise, (A.1) and (B.3) in [II] potentially overlap, because one of Kant's arguments on the teleological argument is that it does not guarantee more than a limited being; but they have to be distinguished because there is a functional difference between appeal ing to Kant and giving an argument that happens to be similar to one that Kant gives. And there are other potential issues arising from the Gifford Lectures and their history, as well -- for instance, Cranston notes that a lot of the anthropological and sociological lectures have nothing to say on the subject, which is of note since anthropology of religion quite obviously plays a large role in the early lectures, and she also notes that the two she classifies as fully approving the teleological argument, Stirling and Stokes, are quite early and that there may be reason for this. The (C.1) group is mostly from the period in which a lot of the lectures were (at least broadly) Hegelian, which fell completely out of fashion, and of course, emergent evolutionism has a significant period in the lectures. Things like these may indicate philosophical fashions and interests in early twentieth-century Scotland more than any broader features directly relevant to understanding the teleological argument. And of course, we will in a few years have a sample of Gifford Lectures a hundred years larger, which might shift around how things work, if one were to try the same thing today.
On the other hand, Gifford Lecturers have been fairly diverse, and deliberately so, and anyone who has done any serious reading on teleological arguments can recognize all the classes noted in her account of the Gifford Lectures objections. In any case, it is worth keeping Cranston's work in mind if one does any analysis of teleological arguments at all.