Suggestions for Harbeth P3ESR speakers

Last year I purchased a used pair of P3ESR speakers in cherry finish for my study. The gentleman from whom I bought the speakers also had a Naim Unitiqute (first version) that he sold to me at a decent price. While I liked the combination, I always felt that the Unitiqute was a little under powered for driving the Harbeths to their full potential. To make matters worse, the digital display (green LCD) on the Unitiqute started to fade and eventually went out after a few months. Searching on the internet revealed that this is a common problem with Naim amps. On one hand, they recommend that the amp be kept on at all times for optimal performance, but on the other hand they use substandard parts for the display. What a shame! So now, while I can still listen to music, I can't really see any information on the amp. Cannot listen to the internet radio, which was a feature I enjoyed, anymore 'cause I can't see the display.

So now, I'm in two minds. Will getting another amp make the Harbeths open up further? Or am I better off selling them and trying something else instead. I already have a pair of KEF LS50 Wireless that I really like and enjoy. KEF has come up with a smaller version (LSX), which is worth a try.

If I decide to stay with the Harbeths, what other amps can you folks recommend? 

Limitations: Have to buy used, under $2000 preferably. Small footprint preferred since it's in my study (10x12x12).

Music: Mostly jazz (including modern), vocals (Diana Krall, Gregory Porter, Nina Simone), soft/psychedelic rock -- Pink Floyd, etc. Sometimes I do listen to hard rock or mainstream pop also. Don't really listen at high volumes mostly but do like to crank it up every now and then.

Lastly, I think adding a small, fast, and musical sub might also help. Recommendations in this category are also welcome