I think it is, ginny. They call their DK "sport" weight. Can you tell by the knitting gauge/tension? Four ply on 3.25mm needles will give about 28 stitches to 4"/10cm, I think.
I have an American pattern which says to use 'sockweight' 4 ply wool. Please can anyone tell me if this is the same as our ordidary 4 ply or someting different.