couple more links for you to contrast and compare

http://www.birdforum.net/opus/Lesser_Whitethroat

http://www.birdforum.net/opus/Greater_Whitethroat

Heres one with calls on.

http://www.rspb.org.uk/wildlife/birdguide/name/l/lesserwhitethroat/index.aspx

Mike, I've sent you a PM, and hope you find this helpful.

im having a small problem identifying these two by their song. the whitethroat is ok because i see them and so i hear them however the lesser i find very elusive but i think i sometimes hear them. does anyone else have this id problem with the lesser, regards to all, mike