The fake birds have hanged themselves and don’t move anymore. Maybe a cheaper version of the good stuff used last year? Maybe worth revising that, @TriathlonHomes & @GetLivingLondon as more and more seagulls are coming in. And as @Tony pointed out: “They are return nesters and increase with each generation.”
The Scarecrow I spotted seems to work - but not the sitting plastic bird of prey. Worth a try though, isn’t it.