I found only 3 rolls of Fujifilm ISO 100 Superia in Reading this week-end, and we are not short of camera shops. The chap in the shop said it was in short supply.
I have used the ISO400 stuff before and it looks good. I went for the superia rather than the reala, as the reala is described as being more for porrtaits, and I think I'll be shooting more landscapes in Italy.