Audi A4 Avant 2.0 TDi - Winter Tyres - Tally

I thinking of getting winter tyres this year, i have been looking at Pirelli sotto zero 210 i wondered if anybody has any experience of these tyres, Should i buy in September to avoid any shortage later in the year, what are they like if i put them on in September are they all right to run before winter.

Thanls