I own the Tannoy Legacy Arden and have been really enjoying them for a couple of years now.
It would help to know a little about your listening area. I've found that in my room, the Arden's offer the best sound stage when the axis are crossed a few feet in front of my head. The speakers sit about 11' apart and are the same distance from my listening position (give or take 6"). This means they have quite a bit of toe in and the sweet spot is fairly narrow. Great for a listener of one, not great if you need to please several at once. I've tried varying angles including straight out into the room, which yielded a very diffused, unfocused sound. You'd want some degree of toe in my opinion. I also had better results raising the speakers up 8" so the tweeters were right at ear level.
To your direct question about off axis response, I would say they aren't the best when seated off center or standing. They don't broadcast sound around the room the way multi driver speakers can. I liken them to very large, high quality headphones with a narrow focal point (picture flash lights coming out of the speakers instead of flood lights).
In tone, they are a definitely full bodied and a little on the dark side (more romantic, less analytical). They are not shouty or bright in the least even when pointed directly at my head. Treble energy and roll off is completely controllable with the crossover which offers a lot of flexibility.
These are easily driven speakers. I've used a Pass Labs XA30.5 (30 watt class A) and more recently a PrimaLuna Evo 300 (45'ish tube watts). I heard more bass punch with the Pass amp, but the PrimaLuna bested the Pass everywhere else.
Where are you located? Maybe an owner can invite you to demo.