Thank you ALL for your inputs so far!

I had in fact done a search before posting my question, but ended up just as confused as I started. I figured that by posting the specifics of my situation I might get some more direct advice.

What I've been able to glean so far is that there are only two properties I should be considering: the Renaissance Chancery Court and the Marriott County Hall. The County Hall has better views but the Chancery Court is more elegant. In most other respects they are equal or at least comparable. Do I have that about right?

Thanks also for the advice on getting to Dover. We'll be flying Virgin Upper Class so our limo to the hotel is provided free of charge. It's getting from there to Dover that I'm concerned about. The Airport Cars London webpage is unclear--would they be able to handle such an excursion?