Anton,
Power requirements are a hard thing to work with. Sometimes an 8 WPC tubed amp will work with speakers that the manufacturer says needs 15 WPC, sometimes not. It depends on your room size, music you listen to, listening volume... you get the picture, many factors.
I always suggest that a potential Bottlehead post here in the general area asking for a Bottlehead in his area bring over an amplifier, offer beer and good music, and find out what a Bottlehead amp sounds like in your room, with your system. If you can find a Bottlehead with Paramount 300Bs all the better. I tried my speakers at a Bottlehead's house and found the Paramour wouldn't drive my speakers, but I heard something special. I ended up buying more sensitive speakers.
I now have Triangle Zerius speakers. They are floor standers and excel in soundstage and imaging. I'm a soundstage/imaging junkie. Having a speaker that sings with my 3.5 WPC Paramours allows me to upgrade and tweak my amps, with MagneQuest output transformers and plate chokes, upgraded capacitors and some small tweaks that I wanted to do with the extra cash I saved from buying higher powered amps. I have a little more cash to buy LPs too.
Part of the magic with Bottlehead equipment comes from Bottlehead standard designs. In all their amps a single tube, class A amplification, Single Ended Triode (SET), Parafeed output are used. Those first three are about having a clean signal path. Bottlehead doesn't make a push pull amplifier. In push pull there are two tubes that split the duty cycle on the output. With SET there is one tube amplifying the whole audio wave. There is something special about that. You need to hear it.
I have heard several Jolita amps. I haven't by any means heard a large selection. They have been really good sounding amplifiers. They would be an improvement over your current amp. But I will still suggest you hear SET before deciding.
So your upgrade path might be the same as mine. I bought a phono preamp, Seduction, then a line stage preamp, Foreplay, then after new speakers Paramour SET power amplifiers (they come in mono pairs).
One last thought, there are a large number of high sensitivity speakers out there. Just a few are the Pi speakers, Cain & Cain speakers, a range of speakers using Fostex single drivers, Klipsch, The Horn Shoppe (you got to look at The Horn Shoppe's site) and a lot of vintage speaker systems.