Warbler in hedgerow

Observation - Warbler in hedgerow - UK and Ireland. Description: This warbler has been singing in the hedgerow in the field behind our house for a couple of weeks now. I think that it sounds like a Garden Warbler but it seems a bit early for that. Not too scratchy, almost Blackbird-sh song, quite continuous singing.

This warbler has been singing in the hedgerow in the field behind our house for a couple of weeks now.
I think that it sounds like a Garden Warbler but it seems a bit early for that.
Not too scratchy, almost Blackbird-sh song, quite continuous singing.
Keeps out of site in hedgerow.
Any ideas would be welcomed!