In terms of what to use in future I'd say that based on your experience and that of BMbikerider the answer is obvious, stick with Portra. I recall an article with pictures by Roger Hicks who seemed to show that it was relatively easy to produce "strange effects" with Ektar. Unless you arrive in the U.K. at our very sunny and bright period of the year and who knows when that will be then I'd be wary of a 100 speed film anyway irrespective of Ektar problems