but travels frequently to the UK on business.
1) Why not arrange to meet him on a UK trip and spend a half day auditioning all kinds of stuff on Totenham Court Road. There is at least one Hi-Fi store on every block.
2) Stick to audition of UK speakers as it will be best value if shopping in UK. Electronics will probably be driven by choice of speakers and functinality.
Aesthetic considersations (how it looks) are what drives 99% of audio decisions so don't be surprised if he chooses something really cool looking over what you might pick. (Bose or B&O might actually be the ticket)