Sedge warbler?

Hi all,

I heard but did not see the bird from this recording. It was singing the same phrase, loudly, without variation. There was also a sedge warbler about (tall grass and reeds near a stream at the edge of a meadow). I recognise the sedge warbler's long improvisational song – is this something else they do? or was it another bird? Tell me what you think! Thanks!

New Recording 32.m4a