My preferences are strongly Tannoy biased, so I'd take the Kensington SE over the S5, unless it's a very large room. I preferred the former, in the exact same system, for its midrange sweetness and musicality. The bass is quite different between the two; in some ways the S5 is tighter, faster, and punchier than the Tannoy, but in other ways it's also more disjointed and reminds me ever-so-slightly of a subwoofer (a very good one no doubt, but still...). Overall the S5 sounded great; very resolving and tonally very clean/neutral from the mids on up, but my preference was clear. I can understand others going crazy for the S5's qualities.
In medium-large rooms, I'd take the Yorkminster/Canterbury over Kensington. Haven't heard the Westminster, but it seems almost certain to destroy the smaller Tannoys in very large room. A VAC Sigma 160i will pair beautifully with any of the Prestige speakers.
The above demo system consisted of a Clearaudio Innovation Compact w/ Ortofon Cadenza Red, VAC Renaissance III w/ MC phono, and Rogue M180. Granted, the Cadenza Red (nice as it is @ 1.2K) was a bit out of its league here, and the M180 is probably the very *minimum* amount of power you'd want to feed the S5, and certainly NOT ideal. The Tannoys benefit from power up to a point, but don't require nearly as much and can run on far far less.