Saw briefly, heard for a long time, sounded like a reel or a large grasshopper, kept repeating that sound with a few little staccato notes at the end, also had another call, sounded like an alarm call, was very hard to see, flitting around in an large alder, when it flew to another site could see brown back, wings, light colour underneath. Wondered if it could be a grasshopper warbler from the sound but having listened to them on internet call was deeper in sound but similar. Any ideas please?