You would be taking one step forward, two steps back. The 45 watt Croft is plenty enough for the P3. BTW, I’ve owned larger Harbeths and always preferred the P3. There is something about that speaker that is special to my ears! Here ya go!
https://www.youtube.com/watch?v=vF1rWiEhEjY
https://www.youtube.com/watch?v=vF1rWiEhEjY