Since KrazyGeoff told me they were to young to breed, I cut down on feeding, raised the temp back to 27 from 23, and stopped checking for breeding activity.
I had a slight filter problem two weeks ago and the tank got covered in brown algae. Did 10-20% water changes every one to three days.
Along with the cold water changes, the 100W heater was failing and would make the temp fluctuate dependent on the weather.
Usually all 4 bamboo caves had the tail of a plec sticking out, but one of the caves didn't so I thought I'd check to see if it was empty. I shined my torch in and funnily enough, he was on eggs :nilly: