I doubt you will find anything sheepskin lined now, even the dregs of the sales have finished for winter stock most places. If you close up on the brand, Fabio Rusconi, they are stocked on Yoox, Sarenza and quite a bit on eBay, just not those particular shoes. Or call The White Company, they have Outlet shops you amy find these in.
If it's just skater pumps you want, they are everywhere, right down to Primark or New Look. You could buy sheepskin liners from Amazon if you wanted to make them warmer yourself.