No. Seagulls in England make the same characteristic loud, screeching calls as gulls worldwide. Vocalizations are species-specific, not geographically dialectal.
The classic "laughing" kyow-kyow-kyow and piercing keee-ah are identical whether you're in Brighton, Blackpool, or Hokkaido. Local ambient noise (traffic, waves, wind) may alter perception, but the gulls themselves sound the same.
So if a Japanese visitor says English gulls sound "the same," they're ornithologically correct.