I should have explained a little better, one single grain whisky is made from maize and malted barley all the others use wheat and malted barley. The reason the barley is used [apart from it beng specified in the Law on Whisky production] is that they need a source of the enzyme zymase to allow the starch extracted from the "grain" to be converted to a sugar. The grain whiskies all have very different flavours but are no where near as powerful in flavour as malt whiskies.
I doubt that you tasted the grain whisky as such as the blends you quote between 35 and 40% malt and I know that 3 of the brands use different mixes of grain whisky. It may be that the flavour you don't like is coming from some of the malts as they normally use anything between 25 and 40 single malts in standard blends. The cheaper blends usually use between 10 and 25% malt, it's back to you get what you pay for.