If I were building from scratch, and money were not at concern, I would do one of the fancy interlock flooring systems filled in with gravel and fines, with mats over top, as described above.
In previous barns I have been through the very laborious process of reflooring clay floored stalls, and it's a bear. I wouldn't do it again without adding mats or some other form of flooring on top. I've also retrofitted mats in a variety of stalls, and I agree the key points of retrofitting mats are having a good level surface (usual method I've encountered is bluestone or graveldust, thoroughly soaked to level it, or tamped with a power tamper) and having the mats fitted snugly, in as few pieces as possible. Two is the fewest I've been able to manage with the weight of the mats. The 4 X 6 mats have a short shelf life and quickly become difficult to work with, IME. Cleaning under mats that were installed over inadequate drainage is the worst job on earth.
In my current barn, which has clay floors, and in which I do not keep horses up, but allow them to use the stalls as run in sheds except in rare instances when I need to keep them confined, I am planning on a 2 - 3" layer of gravel dust, leveled and tamped, and 3' wide industrial belting installed over the top. I plan on doing this for the aisle as well, and to get them as closely fitted as our patience and backs will allow. (Any mat not tightly fitted *will* shift when a horse pivots or moves in the stall.) This will work fine for my application, but probably wouldn't have sufficient longevity to make sense in a commercial barn where the horses are up 12 hours per day.
As for the OP's concern, this strikes me as one of the details that will add to the marketability of your property, but will not actually add dollars to the value of the property. So I would do what works for you in the present, and is a good investment mid-term, rather than long term value.
I have never kept horses in the UK, and I confess, keeping horses on concrete, even with matting on top, seems odd and counterintuitive to me. They only time I've ever seen stalls on concrete is in a converted dairy barn. Just doesn't seem to make sense to me if you're building a horse specific facility from the ground up, but that may be my American bias. Now, if you had permanent drains installed in the middle of each concrete floor, and then put matting on top of that, that would make tons of sense.
I do agree that you could probably mitigate any of the bad effects of the concrete flooring with matting and bedding, but it's not enough to persuade me to start with concrete by choice.