Hi,
Szívesen!
I live close by to Mammut, so I assume you stayed at the Novotel which is close to the Danube on the Buda side!? Really nice area, that is for sure.
They have really good shops on the Vaci street in downtown. You could find almost all kind of brands, like Rolex, Omega, Patek, etc.
Let me know before ur next visit and I will send you the exact addresses.
L.