CREDIT CARD CHARGES (CNA)

I've used a Goldfish card for some years, not just for the 1% points value but because I'm a Centrica shareholder. I've noticed recently that I'm being charged about £20 per month interest despite always paying my bill on time. Goldfish told me this AM that it is because I use my card abroad. Does anyone know if other credit card companies do that? I'm disappoited that Goldfish are seriously devaluing the points system also, are there any other good schemes around please?

Remus