About 6-7 months ago the amps actively driving the main left and right PMCs were swapped from Linn Akurate/D to Lejonklou Tundra Stereo 2.5, which you can read about here.
The main use of the system is for stereo music, so the existing Linn AV5125/D amp for the centre channel was fine for the time being. However, recently a nice used Tundra 1.2 came up for sale which made swapping out the amps possible at neutral cost. Even though the Tundra 1.2 for the centre isn't a perfect match for the left and right 2.5s, it will be a step close than the Linn amp.
The amp lives on the bottom left of the main rack.