Thanks, had seen focal recommended but seem a bit over what i'd like to spend (around 400). The BW 606 are available at quite a good price but some people say they are overly bright. I know the arcam is quite 'laid back' so I feel a 'brighter' speaker may bring the highs out a bit more and help to widen the sound stage. I could be wrong but some people also seem to dislike the metal drivers claiming they are harsh, is this just personal preference?
metal driver/soft dome, both can be harsh hs nothing to do with the material. A lot of folks get mixed up detail and harshness, if you're not used to it detail can come across as cold and bright.
As you say Arcam traditionally (that's an important word newer Arcam is a very different sound to 20 years ago) is a smoother listen, to bring some pep back you want
more lively speakers. It's about balance you don't want to much of any one thing.
Speaking of, Klipsch and a lively presentation id add the 600rp bookshelves to your shortlist, they need a boundary wall so can sit quite close to the wall behind them.
Others too lookout for second hand
older missions 780s and up just make sure they went back for the mid-range driver recall
KEF coda i quite liked these back in the day
KEF iq5's very nice especially the special edition versions
never heard focal
Try and audition those