The Harbeth 40.2(and 40.1) were in my runner-up camp of speakers - I have heard several Rogers speakers and these (3/5a and 5/9) which I would consider in my runner-up series to another set of speakers I own. Rogers especially out of all the 3/5a speakers I have heard (unfortunately it may be the most expensive).
In the end, if you are down to just two speaker finalists then you should do all the listening yourself - forums and reviews may be useful at getting you a list of 10-20 speakers and then hopefully you have a dealer that carries several of the speakers on that bigger list to widdle down to a handful.
And then it somewhat matters where in the world you are located. In Canada I remembered auditioning the Bryston B60 and Sugden A21a - I greatly prefer the Sugden but the Sugden was about $500 more in Canada than the Bryston so the B60 offered reasonable value. But in the UK the B60 was outrageously priced - Perhaps the import duty there is very high but it was more expensive than the Sugden - Hi-Fi Choice gave the Bryston a mere 3/5 star rating. The Sugden is way better in the UK while it is merely just better in Canada in terms of value for the dollar.
On top of that few people will have auditioned any two speakers in the same room, at the same volume, at the same listening position, with the same music. And even then, it is entirely possible one might like the Harbeth better in one room and the Graham better in another room. Indeed, the Harbeth might sound better with the Bryston than Graham and the Graham might sound better than the Harbeth with Sugden.
This happened to me - different speakers. I audition a set of AN K/Lx speakers (copper cables) and it sounded pretty nice with a Rotel amplifier but that same amp on the J/SPe(silver cables) sounded thin and edgy. Switching to the AN OTO SE tube amplifier and the K/LX sound better but the J/SPe made much much greater gains - the thin and edgy went away and it sounded more whole organic and connected together. Bottom line - the impression one would get would be very different depending on what was being connected. Thus, I am not terribly surprised when people hate silver wiring.
Like I said - if you're down to just two finalists - you have to find a way to get both of them in your home to try - alternately - you could ask dealers to provide contact details of customers who would be willing to let you audition stuff.
You would be surprised how friendly the audiophile community can be - I have been welcomed into several people's homes to audition gear in Canada and here in Hong Kong. I bought my current AN E/SPx AlNiCo speakers largely based on an audition at a guy's home (A Pianist in a Symphony Orchestra) who had special non dynamically limited source material to play massive Chinese drum music.
I would also talk to dealers and tell them what you are interested in. They know their customers. They know what their customers are planning in terms of upgrades. So you may get quite a good deal if they know that customer X is looking to sell their Graham or Harbeth because they want something else. Not everyone wants the hassle of selling online so these customers may take a discount over what they could get selling online just to get cash to make their upgrade. So if you like both speakers more or less the same - then try to get the one you can get a better deal on. And if buying blind then the speaker you know you can resell easier if you don't like them. When my dealer told me a customer was selling his Audio Note K/SPe speakers because he was buying $22,000 Audio Note J SEC speakers - I pounced - I gave the guy cash and my KEF LS-50s (they're easy to sell) and I got the AN K/Spe for a price where I could sell them for more than I paid.
So buy second-hand - let other people pay the depreciation. It's not that Harbeth or Graham aren't good - most of today's speakers are good - the question is only about whether they'll be good for you. And none of us can answer that for you. It's kind of like leather - some people love leather seats in a car but others find that it's too hot and their butt sweats so they prefer cloth - so it's not even about price - some people just like cloth better. The speakers may have a slight rise in the treble band - some people like that "sparkle" while others find it bright. How will you know if you don't try for yourself?
Tannoy has this treble sparkle - I tend to like Tannoy as a brand - their prestige series quite a lot - also on my shortlist. I understand why some folks are put off by their treble. I like it. They've been selling them for like 80 years or some ridiculous number - so a lot of people do.