Wallace is a moderately famous mystery writer and many of his books are available on Gutenberg, so I thought I'd give one a try.
I think "competent " is probably the word I'd use to describe this book. Quite a few bits seemed cliched, but I imagine that's at least partly because other writers have pinched them since.
The plot is a bit odd - it starts out as an elaborate revenge plot (the victim of which seems to me to be more oblivious than he should be, given that he writes crime novels for a living…) and then about two-thirds in, morphs into a locked-room mystery.
Not awful but not great. I may try one or two others in case this wasn't the best example of the author's work.
Doctor Who: The Sands of Time by Justin Richards. 218 pages.
My second Doctor Who novel of the year, and, I'm glad to say, much better than the last one.
This one features the Fifth Doctor, Tegan and Nyssa and makes far better use of continuity references than Scales of Injustice did by using them sparingly and in ways that are relevant to the plot.
It also uses the time travel potential of the Tardis to good effect within the story and builds the plot nicely.
I'd definitely consider reading more DW novels by Richards.