Andi, Forth One started doing the same several weeks ago, with the “Scottish” v/o replacing the very whiney English ones. Their few already-extremely-tired sung jingles have also gone – have NS1 done that too?
I'm thinking its either cost-cutting by Bauer or there might be a company-wide new sung packge in the offing (c.f. the “Heart” debates here and on other Forums).