I followed Spagirl's excellent suggestion and searched for "yet alone" and "[Nigel] Thrift." Doing so yielded the following matches from items authored or co-authored by Nigel Thrift.
From N.J. Thrift, Spatial Formations (1996):
3. For example, recent studies of the landscape as text in cultural geography do not seem to recognise that there is a problem, yet alone address it.
Clearly the conception of the human agent outlined above has connotations for what we can regard as 'consciousness', 'belief', 'self', 'attitude', and all the other terms that are routinely applied to human agents, yet alone for how these terms can be stitched together into elements of a theory of social action like 'class consciousness', ;or 'ideology', or 'hegemony'.
From Andrew Leyshon & Nigel Thrift, Money/Space: Geographies of Monetary Transformation (1997):
But, as Stafford goes on to argue, our ability to recognise, yet alone understand, this new oral-visual culture has been shrouded by two different sets of actors. One of these is the manufacturers of the new digital devices whose sales pitch is bound up with techno-hyperbole. The other set of actors are certain media critics who have inherited the suspicion of non-textualisable phenomena dating from the Enlightenment.
This book also includes two instances of "let alone" performing the same function that "yet alone" does in the quotation above. I'm inclined to credit Thrift's co-author for these instances.
From Nigel Thrift, "UK-Nordic Co-operation: Information and Communication Technology and the Social Sciences" (April 15–16, 1999):
Though there is much work on ICT hardware, software still seems to be a poor relation, in several ways. First, there is little work on how programs have effects. For example, there is the case of credit-scoring programs of the kind offered by companies like Experian which have important economic and distributional effects but have not been studied as such. Second, there is a need to consider the practices -mundane and ethical - of software programmers and engineers. How do these actors work, what are their prejudices, and so on? (see Downey). Then, third, there is the way that software can take a 'life' of its own, programs which no one any longer fully understands, made up of 'legey' software, unexplained sub routines, mistakes, simulations of older programs, and so on, yet alone excursions into artificial life (see Helmreich).
From Ash Amin & Nigel Thrift, "Intervention: What Kind of Economic Theory for What Kind of Economic Geography?" in Antipode (2000) [combined snippets]:
It is also perceived as unexciting; it fails to fire the imagination, yet alone connects with the historical concerns of political economy, such as growth, development, ...
From Nigel Thrift, Non-Representational Theory: Space, Politics, Affect (2008) [in addition to the two instances cited by the poster]:
But I also want to argue that part of the impetus for the increasing interest in the misanthropic side of cities that may not celebrate but certainly dos not shy away from the darker side of human nature lies in the fact that modern urban spaces are increasingly seen as themselves implicated in human imperfectability in that rather more of their substance than was formerly acknowledged takes its cue from models of organization that are founded on the systematic delivery of violence, which are so engrained that we hardly notice their dictates, yet alone understand their origins.
So, bearing these caveats in mind, I want to link these three affects more closely in to everyday life. In doing so, I am certainly not trying to deny that the stronger 'firework' affects like anger and feat do not have their say in the interstices of the everyday—consider only the play of domestic violence or the massive incidence of self-harm as a counter to that kind of argument, yet alone other violent incidents of various kinds (see Chapter 9).
From Nigel Thrift, "The Sentient City and What It May Portend" (April 1, 2014), from Big Data & Society:
There is no reason in principle why other ways of proceeding which hold out for a much greater reciprocity with nonhumans—like, for example, animism or totemism (Descola, 2013)—might not again hold sway, yet alone other ontologies like Shinto which we can see as forerunners of what is to come. Whatever happens, superstition, supernatural explanation, ritual and revelation, mystery and magic, will continue to continue.
From Nigel Thrift, "Open Syntaxes Forum: The Weight of the World" in Journal of Space Syntax (October 26, 2015):
Space syntax is a tool for investigating a quality of the world that we have struggled to describe, yet alone analyse, over many centuries. It is both a language of spatial configuration and a spatial configuration of language, worked out through combinatorics.
What we have here is not "yet alone" being used in the sense of "but by itself [or himself/herself/ ourselves]" or "yet alone" being used playfully as a twist on "let alone" that is peculiarly appropriate to a particular context. Rather it is evidence of serial mangling (over a period of two full decades) of a common phrase ("let alone") by someone who really ought to have been informed by someone along the way that he was using the wrong phrase.
Whether no one edits his work or he has had a series of incompetent editors or (as seems at least as likely as those two possibilities) he has repeatedly overruled their correction of this blunder, Professor Thrift has put together an impressive body of misuse of "yet alone." He is not alone (yet) in this misuse, particularly in his own field, but on the other hand I don't think that the mistaken usage is anywhere near achieving the level of critical mass required to transform it from an error into a legitimate variant.