Spendor A6 vs Harbeth Compact 7ES-3

A toss up. Can't go wrong with either one.
You'll have a great sounding system either way. One is on the floor, one is on stands. There may be WAF involved in appearance.
Listen to both if possible. Take your amp.

completely agree with magnumpi205....flip a coin, aside from having to buy stands for the harbeth.

Well I have to disagree, at least with the fact that Spendor and Harbeth sound alike.
I have not heard the Spendor A6, but have owned Spendor LS 3/5, S5e, SP 3/1P, and SA1.
I currently own Harbeth HLP3-es. Have owned Harbeth Compact 7es2 and 7es3, Monitor 30, and Monitor 20 domestic.
Harbeths to me are much more detailed and clear. They have more PRaT, for lack of a better term.
Spendors, while nice, are just that, not exciting, just nice and pleasant. They don't excite like Harbeths can.
Of course as always, everyone hears differently. YMMV.

I owned both( not 6A's, but 6's) and IMHO the Harbeth is in another league.
Better mids, highs, not as much, but better bass. Much more detail and just all around more complete sound. I have since sold both for various reasons, I doubt I would ever buy another pair of Spendor. I would definitely buy another pair of Harbeth, they are wonderful speakers.
Hope that helps.
Mike