Clarks Nanu Rise GTX
Q (Ben Whishaw) wears Clarks Nanu Rise GTX boots (colour: Chestnut brown) in SPECTRE.
The shoes are worn in Austria, when Q meets James Bond at the Höffler Klinik.
The Clarks Nanu Rise GTX modelnumber 26102996 are not produced anymore, and only availablea at a few places online, for example at this German shop: Schuhe.de.
Note that the Clarks Nanu Hike GTX ("Hike" instead of "Rise") is a similar model, but not same the shoe worn by Q. Q wears the "Rise" model.
Note 2: on Amazon a seller sells a different pair of Clarks but with the image of the Nanu Rise GTX, beware not to buy that model if you're loooking for the Nanu Rise.
About the Nanu Rise
A hiking boot-inspired design, rich leather upper, and eye-catching pops of color give this men's lace-up boot from the Tor collection loads of style and attitude. It has a breathable waterproof GORE-TEX® lining, and features a removable Ortholite® footbed that cushions and supports, along with a durable rubber outsole for superior traction. A casual and cool choice for denim, khakis, and cords.
Thanks to Stirling for the ID