I used to have both the PMC Twenty.23 and Dynaudio Contour S1.4 LE at the same time and also demoed the Dynaudio Focus 160 and PMC Twenty.24 on my system.
Firstly my 23s didn't have nearly the amount of bass in the beginning as later on, they gain some bass after the run in period, which is worth considering if you can find out how much those 23s have played so far.
I have not heard the Twenty5 series, but I have heard the 22, 23, and 24 in the Twenty series and due to similar size and forms I suspect the same sort of differences.
To me the SPL and especially the level at which it can play strong bass is higher on both 22 and 24 than on the 23, but the balance between the bass and mid range is different. The 22 sounds leaner and the 23 and 24 much weightier in the bass. This means at low to medium volume you should get the same sort of bass weight from the 23 as from the 24, but it won't be able to match the 24 at high volume.
The mid range to treble balance is also different, possibly due to a different crossover, different driver impedance, and/or the smaller driver integrating better with the tweeter because of driver dispersion. The treble sounds more open on the 22 and 24, but more balanced and cohesive on the 23.
The Focus 160 didn't have as good mid range as the PMCs in my opinion, but the Contour S1.4 LE did. Both these Dynaudios had bags of bass weight, but were more dependent on the room than the PMCs. In an open space with at least 1m behind them, they would more or less match the PMC floor standers, perhaps slightly stronger for the LE, but when placed say 70cm from a back wall, they thunder and the bass overpowers everything on the Dynaudios. They sound too light with the plugs in the ports, so I'd say they either need semi plugs for the ports, or a large space behind them. The PMCs didn't change nearly as much when moving further or closer to a back wall.