Arcam Solo-Mini is not bright. How do I know? I owned one for a year. (No I am not a dealer.)
There ARE dealers you can trust the word of. Obviously you found someone who does not listen to their own stock before selling it. (Or an idiot or a shark. Take your pick.)
The efficiency/sensitivity of the speakers you partner with the Solo-Mini will matter up to a point. It is rated - on paper - at 25watts per channel but they are very young, supple watts that work out a bit, so don't get too worried unless you want high energy club levels of volume.
From personal experience - I would suggest Rega RS1 bookshelf/standmounts (£390 and 90db into 8 ohms) with some good stands, or Rega RS3 'compact' floorstanders (£684 and 89db into 6 ohms).
I have not heard them, but the new Monitor Audio RX2 standmounts (£500 and 90db into 6 ohms) have a specified power handling of 25 - 100 watts and 8" bass/mid drivers. They look promising and should have more bass than most compact standmounts. They should also be easy to audition alongside the smaller RX1's (£400 I think) at the same dealers.
Rega P2 • Ortofon 2M Blue • Rega Fono Mini • Naim Nait 5i • Naim CD5i • Naim NAT 05 FM tuner • Rega R3 loudspeakers • Naim NAC-A5 speaker cable • Beresford TC7520 • Panasonic DMR-EX78 DVD/HDD • Chord Chrysalis, Crimson & Naim interconnects