A guess--are you using (UK) STRONG flour rather than merely 'plain'?

One thing to try -- there are some premixes of things like special organic malted/seed flour for breadmakers. I've had excellent results with thos.

And Lakeland store has some premixed flour packs for different types of bread just the size for standard breadmakers. They work well in my experience, though of course one might prefer more organic & self-chosen in the long run.