I’ve got a soft spot for Five Red Herrings since it was the first Wimsey I read. It was also the first “train schedule” I’d read, so it didn’t strike me as unusual - it was only later that I found that the “schedule” books were a particular sub-set of mystery fiction in the 20s.
As well, I’ve always appreciated one little joke that Sayers played on the reader. Wimsey’s at the death scene, which looks like an accident. She describes him poking around, with greater urgency, until finally he goes up to the investigating officer and says it was murder because there’s something missing. The officer asks what and why, and then there’s a blank page, with a “Note from the Author,” along the lines of “As the intelligent reader will have already noticed what has attracted Lord Peter’s attention, the details are omitted.”
So personally, I’d say it’s worth a read.